Domestic Hot Priority

Users who are viewing this thread

Scottg

New Member
Messages
7
Reaction score
0
Points
1
Location
New York
Sorry if this has already been discussed, but I've looked and can't find an answer.

We're on Long Island and have a Thermo-Dynamics S-series boiler that provides baseboard heating plus domestic hot through a hot water insert. There is no hot water storage tank. We moved in 25 years ago and converted line voltage thermostats to low voltage with Honeywell RA89A transformers for each heating zone. In an effort to clean up the installation, eliminate using romex for low voltage and provide a C wire for smart thermostats, we've run low voltage thermostat wires and purchased a Taco SR503-EXP-4 switching relay to replace the Honeywell transformers.

The hot water insert in the boiler is based on street pressure (no circulator pump) and whenever the baseboard heating kicks in our showers turn cold. The same can be said for laundry, sinks and the dishwasher. The Taco relay has the ability for a priority zone. Is there a way to utilize this feature to inhibit the heating circuits when domestic hot is in use?

I know we don't have the most efficient setup, but we're looking to solve the cold shower problem and not replace the boiler at this time. The boiler room also doesn't have the space to add a separate hot water storage tank.

Thank you,

Scott
 

Scottg

New Member
Messages
7
Reaction score
0
Points
1
Location
New York
Is the priority switch in the on position In taco control.
Zone 3 connected dhw
The Taco control is not yet installed, but it will only prioritize circulating pumps. The domestic hot is provided through street pressure, not a circulator. I guess another way of asking my question is, "how can I let the Taco controller know I'm using hot water so it can inhibit heating by using its priority switch?"
 

John Gayewski

In the Trades
Messages
2,681
Reaction score
697
Points
113
Location
Iowa
Get a normal water heater and pipe it from the coil.

You would have to Jimmy rig a setup from a flow switch but it's not gonna be a great solution.
 

Fitter30

Well-Known Member
Messages
2,873
Reaction score
459
Points
83
Location
Peace valley missouri
Flow switch in water line wired R toW zone 3. Amazon has them. Also a temp regulator would be needed. What does the manufacturer show for piping in their install manual?
 

Scottg

New Member
Messages
7
Reaction score
0
Points
1
Location
New York
Thank you all for the replies. There is no space in the boiler room to add a storage tank without relocation the boiler. That is a job I'm trying to avoid. I was considering a flow switch, as Fitter30 suggested, but didn't know if that was a reasonable solution. The dhw is 1/2" copper. Is there a recommendation for the switch? High reliability is a prime concern and I don't want to randomly order one from Amazon, especially considering the cycles/day it will experience.

I'm only swapping out the boiler controls and making no piping changes, except for what may be needed to prioritize the dhw. The boiler currently serves dhw and heat, so I don't understand the need for the temp regulator, unless the point is that one should have already been installed.

Thanks again!!

Scott
 

Fitter30

Well-Known Member
Messages
2,873
Reaction score
459
Points
83
Location
Peace valley missouri
Flow switch amazon sells them. Need for a water temp reg boiler has one water temp sensor flow rates vary from sink to tub to shower. Since we only have brand and model dont have wiring diagram but boiler does hold around 16 gallons of water if in heating and its 170° dhw turns on need some protection from scalding temp.

DIGITEN FS-C02 G3/4" BSP Male Thread Brass Water Flow Switch 1-30L/min, 0-2A/ 0-220V(AC or DC)​

 
Last edited:

Scottg

New Member
Messages
7
Reaction score
0
Points
1
Location
New York
Flow switch amazon sells them. Need for a water temp reg boiler has one water temp sensor flow rates vary from sink to tub to shower. Since we only have brand and model dont have wiring diagram but boiler does hold around 16 gallons of water if in heating and its 170° dhw turns on need some protection from scalding temp.

DIGITEN FS-C02 G3/4" BSP Male Thread Brass Water Flow Switch 1-30L/min, 0-2A/ 0-220V(AC or DC)​

Thank you so much for the reply and info!! The boiler is set at 160 and I understand the need to protect from scaling temp. The only real concern are sinks, as all showers have thermostatic mixing valves. We've had this setup, except for the mixing valves, since we purchased the house in 1997. In those years, nobody has been scalded, but I understand the concern. I don't want to go into all the details, but there are others reasons for not dropping the dhw temp.

Thanks again!!

Scott
 

John Gayewski

In the Trades
Messages
2,681
Reaction score
697
Points
113
Location
Iowa
Flow switch amazon sells them. Need for a water temp reg boiler has one water temp sensor flow rates vary from sink to tub to shower. Since we only have brand and model dont have wiring diagram but boiler does hold around 16 gallons of water if in heating and its 170° dhw turns on need some protection from scalding temp.

DIGITEN FS-C02 G3/4" BSP Male Thread Brass Water Flow Switch 1-30L/min, 0-2A/ 0-220V(AC or DC)​

British threads? I don't think that's a great idea.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks