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I have a newly installed gwb8 boiler. Temp. Doesn't seem to…

I have a newly...

I have a newly installed gwb8 boiler. Temp. Doesn't seem to reduce sufficiently when I lower thermostat.

Contractor's Assistant: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?

Happened with original thermostat which worked fine before install of new boiler so installed new nest E thermostat and is still happening.i don't think it's the thermostat. Unit does not appear to be on when thermostat has been lowered but temp stays to high

Contractor's Assistant: Do you plan on doing the work yourself?

Probably not, but wanted to understand possible issues before bringing back the people who installed the boiler

Contractor's Assistant: Anything else we should know to help you best?

If I set thermostat at higher target heat than room temp., the boiler does come on and hearts until room temp increases to target heat, which makes me think that thermostat is working.is it possible unit is heating water too high?

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Answered in 43 minutes by:
3/19/2018
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 9,792
Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial
Verified

Hello, turn the thermostat down 5 degrees cooler than the room temperature, then go to the boiler and tell me if the boilers hot water circulating pump is running and if it is firing or not.

.

Next tell me if you have free standing radiators or in-floor radiant heat... we can go from there without any time limits.

.

My goal is to give you the best experience possible! I hope I have earned a 5 star rating! Please remember to rate my service by selecting the 5 stars at the top of the screen before you leave today.

If you need more assistance, please use the reply box and let me know.

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Customer reply replied 4 months ago
Circulating pump does not appear to be running when the target temp is lower (5 degrees or more) than the room temp. I have hot water baseboard heat.
Customer reply replied 4 months ago
Would prefer not to spend more $ on this service, so no call at this time. Please just e-chat.

No more money is required, any phone call offers you get come from the companys automated system, not from me

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Customer reply replied 4 months ago
If no further charge, then call is fine. Cell # is(###) ###-####

If the hot water pump goes off when the thermostat is set lower, we know that the temperature controls work.... verify that the boiler also ceases firing... it should.

If that is the case, then your system is working properly and apparently its not too cold outside... so that the house cools down slowly.

Phone calls are additional... but you do not need to accept any phone call offers. We can continue here in this dialog box without any time limits

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Customer reply replied 4 months ago
I’m outside of Albany, NY. Temperature outside is about 29 degrees F. Last night was down to 10 degrees and took quite a while for it to cool and never reached target temperature. It is either barely cooling at all or very minimally. I’m not sure, but there does appear to be a bit of residual heat coming from the baseboards even when the circulator isn’t running. Is it possible the water temp from the boiler needs to be lowered?? It was about 150 degrees when I checked a couple of hours ago.

150F is a good temperature range for most boilers, you can try setting it lower but not lower than 130F.

.

It is also possible that there is water circulation with pump not running, this happens when a new system is installed without the proper 'check valves'... tell me about how old the system is,

.

We can go from there.

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Customer reply replied 4 months ago
System was installed this past week (Wednesday) and issue has been going on since the new installation.
Customer reply replied 4 months ago
Service manager came on Friday and indicated the possibility that the original thermostat wasn’t working properly, but I’ve now swapped out the thermostat for a new Nest E. Old thermostat had worked fine up until the old boiler was replaced.
Customer reply replied 4 months ago
House is 1950’s vintage construction with new energy efficient windows, but insulation of 1950’s vintage, so it’s definitely not a super well sealed house. In the past, once the boiler went off (when thermostat was lowered), temp would begin to fall pretty quickly after lowering the thermostat.
Customer reply replied 4 months ago
Tonite I lowered the thermostat from 68 to 55 around 9:30. Room temp was 68-69. It’s now 11:20 here and room temperature on the thermostat shows as 67. It’s barely gone down in almost 2 hours with temps outside at about freezing or slightly below.

Thanks, ***** ***** about 99% likely that check valves were not installed with the new boiler to prevent hot water flow when the hot water pump is off.... any contractor that made such an error would not be experienced enough to know that can happen or would be a problem.... so they will come up with non workable solutions.

You can tell if that is happening or not by turning power off to the pump, then feeling the piping in and out of the base boards, if the water is hot. ... then there needs to be check valves installed in the piping. That is called gravity induced flow, cooler water is heavier than hotter water, so that the cool water flows down and forces water into the boiler.... that water forces hot water out of the boiler and back to the baseboards.

.

there is another issue, a competent boiler installation will have a 'flow switch'...that is wired to keep the boiler off unless there is substantial hot water flow, gravity flow of hot water should not be sufficient to provide that flow.

I see those two errors in the installation so far.

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Customer reply replied 4 months ago
When you say to check the pipes in and out of the baseboards, you mean to check the pipes coming from the floor into the baseboards? How long after turning off the heater should the pipes be cold?
Customer reply replied 4 months ago
Where do the check valves get installed—at the boiler or at each baseboard??

Yes, pipe coming through the floor to the baseboards... that pipe should start cooling off within 10 minutes and be at room temperature within 20 minutes if there is no gravity induced hot water flow.

.

a careful study of the piping needs to be done in order to prescribe location of the check valves, and dont forget you also need a 'flow switch'

https://inspectapedia.com/heat/Check_Valves_Heat.php

click that link, see the piping diagram and explanation.

,

Its time to rate my input for the day, that gets me paid, locate the "finish and rate your expert" link near the top of the page and click on it. I will appreciate that very much.

I am in every day from 9 am to 11 pm west coast USA time to do any follow up needed.

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Customer reply replied 4 months ago
I’ve shut down the boiler about 5 minutes ago as I was waiting for your response. System seemed to work fine until last boiler failed after many years of reliable service. Would it have had check valves already installed, or are they something that gets installed as part of a new boiler installation?

Any slight change in the piping with the new boiler could be enough to enable this gravity flow... so that your old boiler may not have needed them but the new boiler would.

Did the hot water line going to the baseboards cool off when pump was shut down? Keep checking,

and check both pipes at each base board to make sure you have the right one.

click here for a bunch more diagrams

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Customer reply replied 4 months ago
Will rate you after one last question. Would a flow valve be installed internally in the GWB8 unit. It’s a brand new unit. Or would it need to be external and visible in the pipe configuration around the boiler set up?

The flow switch is generally installed in the boiler water return line,

click here for the boiler manual

No flow switch is shown in the boiler itself, nor is it shown in the piping.. Lennox is assuming that if the pump is running there will be hot water water flow... most manufacturer will not take that chance and will install a flow switch wired to kill power to the gas valve if the flow fails due pump failure or vapor lock in the piping.

.

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Customer reply replied 4 months ago
I was asking about the flow valve, rather than the flow switch. Would the flow valve always be external to the boiler and visible, or is it sometimes within the boulder itself and not visible without opening the boiler? Is there anything I can say based on what I’ve described to you to show the service person that this is unlikely an issue related to the thermostat?

Yes ... what you are calling the 'flow valve' is actually a back flow preventer, or a 'check valve' it is not shown as part of the boiler, in my 58 years as boiler contractor I have never seen a check valve fit as an integral part of a boiler... these are always fit external to the boiler by the installation contractor as shown in the diagrams I posted earlier.

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Customer reply replied 4 months ago
Thanks. I will enter a rating. If I have a follow up question tomorrow, is that a separate charge?

There is no charge for follow up questions on the same issue after you rate my work. Thanks for your consideration, use the 'finish and rate your expert' link near the top of your page for that... just click on it, and follow the prompts

Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 9,792
Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial
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