Radiant heat problems/questions????????

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Fraser Jim

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Happy Thanksgiving

We built our retirement home 5 years ago. Use on weekends. In Colorado - gets to 20-30 below during winter.

Plumbing company totally incompetent. Leaks, Wrong valves, toilets not seated, stuter vents leaking, shower valves clogged, etc.

Two stories. No bsmt.

Buderus G234X-38 Boiler

First floor about 1,900 sq. ft, 5-radiant heat zones

Second floor about 700 sq. ft, 2-baseboard heat zones

Domestic Hot Water on boiler

Highlights of plumber's screw-ups:

One two loop RH zone didn't work. Plumber insisted that there was air trapped and he hooked up external pump to pump into return of zone and force air out of supply side. After three attemps, no better. I looked and saw that there was no shutoff between supply and return manifolds. I asked why and he said that it wasn't in plans. I said that I didn't see how he could pump through zone if the two manifolds weren't isolated. The next week there was a shutoff. GC found that the plumber had hooked up one loop of the zone to the supply side and the other loop to the return.

Once we moved in, I noticed that the boiler was always firing during hte summer. I traced wires and found that the plumber had miswired one of the Taco Relays and it was always calling for heat.

More information.

Taco AAVs above expansion tank and on DHW tank. Spirovent vent on supply manifold on input to radiant circ. pump.

Watts 174A M3 relief valve 30psi

Watts auto fill - I have this shutoff

Amtrol Radiant Extrol RX30 tank

Wirsbo hePEX 3/4" and 1/2" tubing

I have 4 pressure gauges installed because of problems. 1. on boiler 2. on supply line between boiler and expansion tank 3. On rad. heat supply manifold after circ. pump 4. on baseboard supply side after its circ,. pump.

Problems:

1. Up till this year, we would come in and pressure relief valve pipe would be seeping. Plumber has replaced PRV and Expansion tank three times. I have never seen pressure over 23psi on any gauge. Seems to be ok when we are in home and keeping temps. about 68. Seems to be a problem after we come in after a week and system temps in 50s and we turn on heat. It would vent after about an hour after we turned up heat.

Plumber didn't record how much tubing he used, so we are guessing at capacity of system, but others say tank size is ok. Also, he didn't know how much glycol he put in system.

What should the range of pressure be on system when system is off (summer)? last year was about 5psi, this year about 2psi

What should pressure be when everything is on? Last year about 23psi, this year 21psi.

If the system has been off and we turn on heat and it is about 8-9 psi, it will climb to about 16psi in 10 minutes.

2. About two years ago heard gurguling sound from mech. room. Looked in and the Spirovent and Taco AAV on DWH were spewing glycol. Enough came out of DWH that it filled up well for thermocouple. Shutoff system and let sit. Restarted and everything seemed ok. There was black flecks in glycol that looked like coarse ground pepper. Seems fine since then.

Plumber said to keep the AAVs shut and occasionally open. I open about once a week and they will hiss for about a second.

Should they be venting air after two years??? Should they be left open??? I am concerned that if we are not here, whole system may vent.

3. Checked out second floor baseboard and saw no AAVs. I baseboard zone ticks when turned on. How are you supposed to purge air out of baseboard? Do you need to?

I guess the most important question is what should be pressure ranges from cold to hot on system.

Thanks

Fraser Jim
 

Rmelo99

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had written about a page when the battery died! Ughh...gimme a few and I'll rewrite it!
 

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Ok so I'm no pro but have done a lot of research on hydronic heating for my own system. I knew I wanted a complicted system(like yours) but

a.) didn't trust the local plumbers to tackle this
b.) the ones who are competent enough to do what I wanted would have bankrupt me!

That being said I designed and built my own system with help of the internet.

It sound like you have several problems that need to be addressed. You biggest issue as you have identified is AIR.

There are 2 reasons air is such a problem in hydronic heating.
a.) air trapped in a zone or part of the system will prevent heat from getting there.
b.) RUST. If your system has any ferrous metal (cast iron boiler, cast iron circulator, etc) then you do not want to have air/oxygen in your system.

You do not want to be adding fresh/makeup water to your system, this will continuosly add oxygen and can ruin your equipement and wallet. Getting the air out initially is the most important. This isn't too difficult if the system is designed with purging air in mind. That means isolation/purge valves in the proper place for each of your zones.

It sounds like you had this problem at your manifolds and may have been corrected. The fact that it wasn't thought of originally worries me that the design wasn't well thought out!

Your baseboard zone doesn't need aav or bleeders if it is piped in a loop. Purging the air out of that zone can/should be done in the basement at the return side of the zone with proper isolation using valves. Or in your case in the boiler room @ the boiler.

PSI- The range is have seen is 12-22 or so. This depends of the elements of your system and what the PSI has to overcome. It should not be swinging 8-9 psi while heating. That is WRONG and will be causing you to blow your PRV which usually are set to 30PSI. PSI should not be dropping it should remain steady. You are losing pressure somehow.

Pressure problems are caused by a bad or undersized expansion tank, a bad auto-feed valve and general air problems in the system.

Sounds like the guys who have come out aren't equipd or knowledgeable enough to be working or building a system like yours. They may be in over their heads and not willing to admit it.

AAvs are just that auto, and they don't need to be open/closed. Now if they are bad or have failed they may not be working, but in a working system they just let air out!

When you say "vent out" i'm assuming you are worried about losing the water in your system while you are away. I would be too, bc that can mean DEATH to your boiler. You did not mention a LWC(Low water cutoff). Given this is a new system it should have one installed. Most boiler manufs and codes require them. This is an absolute must have, please confirm you have one.

You need to figure out the AIR situation. It needs to be properly purged when initially filled. I would start there. Now if you continue to have air introduced then you need to identify how it's getting in. Leaks will do that as well as not a good seal at the circulator and it sucks air in when running.

The airscoops and AAV handle getting rid of the small amound of air that can sometimes be left behind. If you have big pocket of air that was never purged it can travel around the system and cause problems all over the place.

Each zone needs to be filled and purged seperatley.

If they don't know how much piping was used shame on them. A pro can approximate the amound of tubing to within a tolerance that he can properly size the expansion tank. You can also try filling and draining the system to measure the water capacity.

I do not run glycol in my system, but know that certainly adds complexity.

I would bring in a few different companies with references as to working with hyrdronic design/radiant design. Pick one and have them help you address design/mechanical issues with your system before it costs you more money.
 
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Fraser Jim

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Thanks remelo99,

We have had four different local "experts" out and they all are shaking their heads on the PRV opening.

No a LWC wasn't installed. Sounds like a good idea.

I installed a Sensaphone Auto dialer and I can tie that into the LWC.

The autovalve is closed and I haven't added water to the system in two years.

Just a slight drop in maximum pressure during that period, so I am pretty sure that there isn't a signifcant leak.

We are in the Winter Park / Fraser Colorado area, so if anyone can recommend someone who really knows what they are doing, I would appreciate it.

FJ
 

Rmelo99

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The system needs to be able to maintain pressure even during the summer in off mode.

2 or 5psi is too low. I would say it shouldn't be less than 12psi. You may have a leak in the radiant, which is why you don't see it.

Is your radiant in a slab? Hardwood over it? If no one has done a pressure test with air on the seperate zones and boiler piping of this system I recommend doing that. There has to be an explanation for the pressure swings.

You say you haven't added water in 2years but you are expelling air? What is filling the space that was being taken by that air? Unless there is a specific reason you have the auto-fill shut off I would reopen it. You need to replace the air space with water. You don't just remove air...you push air out and replace the space with water.

You also say you have had the PRV leaking water, again that water needs to be replaced with something! It worries me if what you say is true about not having added water in 2 years!


You also shouldn't be watching the maximum pressure. Your boiler while cold needs to maintain a stable NON moving PSI. Your PRV also can be opening due to temperature. If the water in the boiler is boilng over (VERY BAD) and creating steam then the PRV will open to exhaust it. This is not due only to increase in pressure.

Any leak is bad it doesn't have to be significant. This is supposed to be a closed system.
 
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Fraser Jim

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We have radiant within slab covered by hardwood or slate.

Bad news if we have a leak.

I have keep the auto-fill off in case we do spring a leak, we will limit the amount of damage.

The PRV hasn't leaked this year.

Sounds like the pressure test is the best move.

I presumed any air in the boiler would be shot out of the supply feed and get removed when it hits the air purge which is in line with the expansion tank and an AVV.

FJ
 

NHmaster

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Fraser Jim, go here www.heatinghelp.com and post your problem. If you can do some pictures of the boiler, piping and manifolding it would be very helpful. sounds to me like you have some very unbalanced loops. Un-equal loop length off the same zone will always be a problem to purge the air from in the first place and then balance. The autofill should not come into play once the system is full and purged of air. In fact, I rarely use an auto fill on a radiant system because i usually anti-freeze them. At this point I can't give a lot of advice because I don't know if you have a primary secondary system or injection, 4 way valving, variable speed circulators, In short we need more info.
 

Doherty Plumbing

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If the system has been off and we turn on heat and it is about 8-9 psi, it will climb to about 16psi in 10 minutes.

2. About two years ago heard gurguling sound from mech. room. Looked in and the Spirovent and Taco AAV on DWH were spewing glycol. Enough came out of DWH that it filled up well for thermocouple. Shutoff system and let sit. Restarted and everything seemed ok. There was black flecks in glycol that looked like coarse ground pepper. Seems fine since then.

Plumber said to keep the AAVs shut and occasionally open. I open about once a week and they will hiss for about a second.

Should they be venting air after two years??? Should they be left open??? I am concerned that if we are not here, whole system may vent.

3. Checked out second floor baseboard and saw no AAVs. I baseboard zone ticks when turned on. How are you supposed to purge air out of baseboard? Do you need to?

I guess the most important question is what should be pressure ranges from cold to hot on system.

Thanks

Fraser Jim

1. For a two story building I wouldn't run anything less than about 17-18 psi due to head loss. At all times...

2 (a) That sucks!!!!

2 (b). He's wrong. Their automatic air valves for a reason.... they're meant to automatically remove air. You shouldn't have to decide when to open them etc. Just leave them on. If they give you issues then you have other problems. Air in the system is the worst thing you can have.

3. They might have a coin vent, wheel vent or something similar at one end.

4. If your expansion tank is working properly you shouldn't hardly notice a difference in the pressure at all in a cold vs hot system. The expansion tank is there to eat up the excess pressure caused by thermal expansion. If your pressure goes up dramatically from a cold system to a hot system you have an issue. Either the expansion tank is failing, undercharged or undersized.

Your expansion tank should beable to eat up 4% of your systems volume.
 

Doherty Plumbing

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Your baseboard zone doesn't need aav or bleeders if it is piped in a loop. Purging the air out of that zone can/should be done in the basement at the return side of the zone with proper isolation using valves. Or in your case in the boiler room @ the boiler.

This isn't true what-so-ever. You want AAV or bleeders at the HIGHEST points in the system. Putting them in the basement (except for the spirovent) is basically pointless. And trying to purge a piping system from the boiler room (which is the lowest point) is pointless as well. Always bleed from the highest points in the system.

Air ALWAYS rises in a piping system.
 

Rmelo99

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This isn't true what-so-ever. You want AAV or bleeders at the HIGHEST points in the system. Putting them in the basement (except for the spirovent) is basically pointless. And trying to purge a piping system from the boiler room (which is the lowest point) is pointless as well. Always bleed from the highest points in the system.

Air ALWAYS rises in a piping system.


While I agree with you about having bleeders and AAV's at the highest point, depending on the way his baseboards are piped it can be such where they are not an absolute necessity. For the small amount of money adding them costs vs. the headaches of not having them costs I would definantley advocate for them.

There are several ways his system can be piped. (we don't know how his is piped) If the baseboard zone is using the radiators to make the loop piping then there is no reason why you should not be able to purge the air out of that zone at the boiler room. Any other piping method would def require bleeders upstairs for sure.

If you are looking for AAV size units in the baseboard that may be your mistake. They usually have manual bleeders which are TINY and can be either hand opened or require a small special key.
 

Doherty Plumbing

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While I agree with you about having bleeders and AAV's at the highest point, depending on the way his baseboards are piped it can be such where they are not an absolute necessity. For the small amount of money adding them costs vs. the headaches of not having them costs I would definantley advocate for them.

There are several ways his system can be piped. (we don't know how his is piped) If the baseboard zone is using the radiators to make the loop piping then there is no reason why you should not be able to purge the air out of that zone at the boiler room. Any other piping method would def require bleeders upstairs for sure.

If you are looking for AAV size units in the baseboard that may be your mistake. They usually have manual bleeders which are TINY and can be either hand opened or require a small special key.

Again not true. Not to sound rude but how many boiler systems have you installed? And how many boiler systems have you gone out and repaired?

Saying you don't need bleeders on the rads at the hightest point is absurd. You need bleeders at the highest point always. The pump won't overcome an air lock in an upstairs rad to push that air DOWN (while it's trying to float back up) and then through the spiro vent to be eliminated from the system.

No matter how the system is piped you need bleeders on the highest points of the system if you plan on actually getting 99.9% of the air out.
 

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I agree you have prob installed and worked on many more systems than I have. You are most likely a pro so I won't argue with your methods. There is more than one way to skin a cat. I'm sure your systems are well installed and work well because you know how you put them in and how they are piped.

All you mention about air locks and overcoming pump head are true and accurate.

I will be the first to admit that the field of hydronic heating is and art and a science at the same time. There are too many variables to help anyone out without seeing the exact system firsthand and seeing the problems first hand.
Many plumbers can fix basic problems with a boiler system. Many can swap out a simple boiler for a new one. It is also very easy for someone who isn't familiar with a boiler sytem (simple/complex) one to really screw things up!

I learned to and always done my initial fill and purge of a loop manually and not relied on the pump(circulator) to get the water in and air out. The circulators should not be pumping water into a zone it should be just moving water in a closed syste. Once I have the water flowing at my purge valve down at the return in the boiler room I know there are no air locks to be worried about for that zone.

If the zone is piped anyother way then a loop integral with the baseboard then any given rad can have an airlock that will require a bleeder of some sort at the unit(esp the ones upstairs).
 

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If you set your primary pump correctly (pumping away from the boiler and past the expansion tank) 99% of your air problems are eliminated. Read Dan Holohans book Pumping away for diagrams and technical explanations.
 

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I agree you have prob installed and worked on many more systems than I have. You are most likely a pro so I won't argue with your methods. There is more than one way to skin a cat. I'm sure your systems are well installed and work well because you know how you put them in and how they are piped.

All you mention about air locks and overcoming pump head are true and accurate.

I will be the first to admit that the field of hydronic heating is and art and a science at the same time. There are too many variables to help anyone out without seeing the exact system firsthand and seeing the problems first hand.
Many plumbers can fix basic problems with a boiler system. Many can swap out a simple boiler for a new one. It is also very easy for someone who isn't familiar with a boiler sytem (simple/complex) one to really screw things up!

I learned to and always done my initial fill and purge of a loop manually and not relied on the pump(circulator) to get the water in and air out. The circulators should not be pumping water into a zone it should be just moving water in a closed syste. Once I have the water flowing at my purge valve down at the return in the boiler room I know there are no air locks to be worried about for that zone.

If the zone is piped anyother way then a loop integral with the baseboard then any given rad can have an airlock that will require a bleeder of some sort at the unit(esp the ones upstairs).

There are many ways to pipe a boiler system that's very true.

However air always rises. And if your piping is going up and down (IE from one room to the next and up into the rad, back down under the floor to the next room then back up etc. These are all places where air is gonna get trapped. You need a bleeder basically any time you create a possible air lock situation..

And yes circulators do move water into zones and not just through a primary/secondary system. MANY houses are designed so that when a zone valve opens the end switch trips a relay and this brings on the pump, then the boiler. In fact most houses up here are not piped with hot loops. Commercial stuff is though!

Your way of purging is great when you 1st fill the system up. But if lets say you have a slow leak and you're bring in fresh water/air there is a chance air is gonna build up and air-lock at the highest points.

Blowing the line out at the boiler only introduced more fresh water/air and the cycle will continue. However if you have a bleeder at the higest points you can just simply bleed it until you get a solid stream of water. This will minimize the fresh air/water you introduce into the system.
 

Rmelo99

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You are right on the bleeders help get air out that works it's way into the system down the road.

A leak is a leak to me. I take it very seriously. I want my system to be truly a closed one.

I've invested a great deal of my time and money into what I consider a high-end heating system. It disturbs me that many people don't feel the same way I do. I'm not sure what the original poster has spent on his system, but by the description I wouldnt call it a drop in the bucket.

You wouldn't have a back yard mechanic work on your 2010 Porsche! Either the dealer or a specialist. If the dealer you bought it from turns out to have a crappy service center your find another one, because anything those hacks do to your car will be your problem down the road.
 

Doherty Plumbing

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You are right on the bleeders help get air out that works it's way into the system down the road.

A leak is a leak to me. I take it very seriously. I want my system to be truly a closed one.

I've invested a great deal of my time and money into what I consider a high-end heating system. It disturbs me that many people don't feel the same way I do. I'm not sure what the original poster has spent on his system, but by the description I wouldnt call it a drop in the bucket.

You wouldn't have a back yard mechanic work on your 2010 Porsche! Either the dealer or a specialist. If the dealer you bought it from turns out to have a crappy service center your find another one, because anything those hacks do to your car will be your problem down the road.

Exactly. And putting bleeders where they're needed is a great, cheap-in-the-long-run solution to having a trouble & relatively maintenance free system.

I couldn't imagine installing a system and not putting bleeders where air is most likely to get trapped. Regardless of what some guy in a book says about because he's probably an engineer living in a perfect math world where everything works great. I'd trust my real life experiences over a book.

I have worked on many systems that were not designed properly or didn't have proper bleeders etc. Sure the system works but you don't get the flow rates you should because the system still has air trapped in it from 10 years ago. After I install bleeders and get the system 99.9% free of air the 1st thing I usually hear is "Wow the system has never worked so good."

Air is the biggest enemy of any closed loop hydronic heating system.
 

Fraser Jim

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Thanks guys,

It is getting late and am full of turkey.

Some quick answers.

I work in the electrical field, so pardon some of the terms I use.

They piped out of the boiler and the first thing it hits is the expansion tank / air purge / and an AVV.

It then branches off to three feeds.

#1. To a main loop, which has a Taco circ. The main loop has a tee that ties a variable speed circ. feeding the radiant supply manifold. It is controlled by a TECMAR 361. The feed from the main loop ties to the supply manifold and then hits the Spirovent and then hits the radiant heat circ. No other valves / 4 ways, balancing, etc.

I am concerned that the top of the main loop sits about 18" above the Spiro and two AAVs.

#2. The feed to the DHW. It has a circ.

#3. The feed to the baseboard. It has a circ.

Questions.

So, all baseboards on second floor should have some type of an air vent? Are they usually built in or does the installer have to add them externally?

If there is air in a baseboard, will it have heat coming out the return end?

I wouldn't be surprised at anything. 4 out of 5 zones are anywhere from 120 to 200 sq. feet. The fifth is probably close to 800sq. feet.

Attaching some pics. Sorry for lousy quality. Had to resize to fit rules.

#1
-Boiler - blue on lower left.
-Expansion Tank behind boiler
From top
-Main loop across top
-Variable speed circ pump going down to supply manifold
-Spiro and then radiant circ.
-Main loop circ.
-Baseboard circ
-DHW circ

#2

-Variable speed circ down to supply manifold

#3

-Supply and return manifolds.


I will get some more pics tomorrow and also post to Heatinghelp!

Regards,

FJ
 

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hj

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heating

WAY too much reading to do if I tried to review what everyone has stated previously. In a nut shell, the AAV's should only vent after the system is filled initially, UNLESS, you have vacuum vents and and pressure were to drop for some reason and draw air in. Otherwise, the ONLY ways to get additional air is by adding water to the system, which would be bad for a glycol installation since it would be continually diluted, or through tubing which does NOT have an oxygen barrier, in which case it is the wrong PEX for a heating system. You also cannot "bleed" baseboard loops by purging them once the glycol is added, but then neither should you have to. You need a competent service technician to check it out and see if there are any "permanent" problems which cannot be fixed easily. As far as pressure is concerned, if the tank is the correct size for a glycol system, not a water one, then as long as the pressure is adequate when the system starts, and does not rise to the point where the safety valve discharges, it should be okay.
 

WPHomer

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Heating help in Fraser

Hello Jim,

I have a good heating guy, in Fraser. I am in Winter Park, and have good success with A Heating Connection. If you are still in need, get back to me, and I will send you Dave's phone number.

Steve
970-281-9565
 
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