DR-DEATH
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Ok thank you. You guys have been so helpful and I really appreciate the help. Will update when they are back.
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Navien NCB-240E possible purchase
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The air scoop appears to be at the expansion tank (which is a common, and good configuration), but it will work more effectively when installed correctly positioned relative to the pump, with the pump pumping away from it rather than toward it, and with the requisite minimum amount of straight pipe on both sides of the air scoop:
This is really a hydronic systems 101 type of detail, and there isn't much excuse for screwing it up on a new installation where there is plenty of room to work with. (It's sometimes awkward when re-working on an older system without ripping the whole thing out first, which the customers don't want to pay for the extra work, and would rather put up with having to replace a pump every 7-10 years or whatever.)
This is really a hydronic systems 101 type of detail, and there isn't much excuse for screwing it up on a new installation where there is plenty of room to work with. (It's sometimes awkward when re-working on an older system without ripping the whole thing out first, which the customers don't want to pay for the extra work, and would rather put up with having to replace a pump every 7-10 years or whatever.)
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DR-DEATH
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Final conclusion is both master plumbers felt the expansion tank was fine and where the pump was fine and that there's enough straight pipe at the air vent/expansion tank. I brought up the pump not being horizontal and they said it shouldn't be an issue as pressure will be above 20psi etc. the taco control did not fix the issue. The end switch was bad apparently. Was only charged for the part not the labor for requiring the valves and taco controller. All in all the total cost was $3590 after a few rebates. I now just need to fiddle with the pump setting (still on high only) and the outdoor reset.
I hope this system will last and do everything I need. Thank you all for the help, I can't imagine not having this resource.
I hope this system will last and do everything I need. Thank you all for the help, I can't imagine not having this resource.
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Congrats on the install!
The price was reasonable.
The ODR is kind of difficult to dial in during a shoulder season. I've kind of come to the conclusion that until I really get to know my system well I'll use a temporary reset curve that works now.... then re-tweak it during the real winter season.
The price was reasonable.
The ODR is kind of difficult to dial in during a shoulder season. I've kind of come to the conclusion that until I really get to know my system well I'll use a temporary reset curve that works now.... then re-tweak it during the real winter season.
DR-DEATH
Member
I was wrong on price. I meant $2,590 after rebates. I figure I'll make that back within 3-5 years of gas savings. Should I at least put the pump on constant pressure? Which setting would you recommend as I'm not sure about head etc.
DR-DEATH
Member
Everything seemed to be running within factory spec out of the box. Running the dip switch on low fire while testing showed 98% effeciency, not sure what high fire was though. Stills makes a Perkolating noise so I'll keep an eye on that. The plumber said he was going to call HTP to see what they say about the noise.
Generally you'd like to have 1-2gpm going through each zone.
The minimum flow rate for the UFt-80 is 1 GPM, so don't go below that.
Does your pump have a display like the Alpha that indicates GPM rate?
FWIW- the gas valve adjustment screw only adjusts the low fire air/gas mix, you can only observe the high fire readings- there is no adjustment for it.
I bet HTP will tell your installer the percolation sounds will end over time used once all air is out of the system.
DR-DEATH
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The pump does not have a display that shows gpM. I switched the pump to constant pressure mode at the 10 number. Not sure how to read that with the chart. All I know is it pumps slower than max and lowered return water temps.
Your installer should have calculated your system head and set and tested the pump.
That shouldn't be left up to the homeowner to determine the CH pump settings.
Without a display on the pump or a flowmeter/circuit setter installed- you'll have to do a rough system head calculation, set the pump accordingly and keep an eye on the SWT and RWT of your zones.
That shouldn't be left up to the homeowner to determine the CH pump settings.
Without a display on the pump or a flowmeter/circuit setter installed- you'll have to do a rough system head calculation, set the pump accordingly and keep an eye on the SWT and RWT of your zones.
DR-DEATH
Member
They didn't like the idea of using an ecm to be honest. But now I wish I had the grundfos to have it show gpm.
Leon82
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Observe the boiler and delta t on each setting. If the pump cant overcome the head the boiler would reach the high limit
DR-DEATH
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What happens if the flow goes under 1gpm? Is it bad for the boiler?
DR-DEATH
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Gotcha. I am assuming that's not a huge deal if it happens a few times while tinkering with it - just can't let it short cycle every time though. I guess I could run the pump on max setting and not worry about it but probably have higher return temps and not condense as much - guess we will see.
Leon82
Member
I suppose high limit is the wrong word. It would reach the setpoint and turn off
DR-DEATH
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I was watching the boiler today. Outside temp was 29 according to weather app but ODR said 36. (North facing) I turned thermostats up from 65 to 69. Boiler kicked on at a higher rate and heated the water up to around 150 for about 5-6 mins and then the burner must have kicked down and let the water temp drop to about 136 while burning at a lower rate for about 9 mins and then water started rising back up to about 145-155. 23 mins of total burn time temp was back up to 153 at 29f outside. So it appears to have long burn times if I'm understanding this correctly. I couldn't see the burner on because the cover was on but the flame sensor was showing it was burning on the control panel. It seemed to condense most of the time until it got to 150-155 as the control panel said return temp was 140. May have to fiddle with the ODR.
Leon82
Member
My lochinvar sensor reads high too.
At 29 degrees my starting water temp is about 120 or so. I would go down until it struggles to maintain temp and then go back up about 5 deg at a time
At 29 degrees my starting water temp is about 120 or so. I would go down until it struggles to maintain temp and then go back up about 5 deg at a time
