Hot coming out of cold... Boilermate/Coil issue?

Hi all,

I'm reviving this one because our AC/heat pump company came to take a look while they were doing spring start up on that system last week. they said leaving the coil in is perfectly acceptable but that it would be better to close both hot out of coil and cold coming in and I shouldn't need to worry about any boil off or anything (the tech said his mother has had the same setup for 15 years after she added an amtrol tank to the system).

He did say however that it was silly to have the boiler running when nothing needs it and recommended changing the aquastat (mentioned a honeywell 8148A) and setting it up for cold start so that unless a zone (hot water baseboard or hot water amtrol tank) is calling for it, the boiler won't run at all.

Based on feedback, it sounds like some of you might not agree with the first part (leaving the coil in) but would agree with the cold start of the boiler, right? Is there anything so bad with this proposed setup?

One thing I don't get is let's say that the boilermate dies one day. I can close the valves to/from the boilermate off, and open the ones to/from the coil, but since potable hot water isn't a zone (unless it's coming from the boilermate), then I don't think the coil will make hot water in a cold start setup because there won't be a zone calling to turn it on, right?

Most indirects will outlast the boiler firing them, so it failing is generally not something you have to worry about. If you change the aquastat to cold start, then you'd have to change it back to use the internal coil. Personally, I wouldn't worry about it and disconnect it.

Regular cold starting, especially if it is a short cycle, can be problematic on a boiler. But, the burn time to reheat the indirect should be long enough to not be a big problem, then, it likely wouldn't need to come on again for quite awhile (most indirects have decent insulation, and you may only need to crank it up once a day, if your heavy use is in the morning for showers.

What about in the winter when our heat pump can't keep up and we're using the hot water baseboard. The tech said they'd set the temp at 180 because you need that for the hot water baseboard system coming back in but so I need to worry about short cycling if say a heat zone called for it?

Yes, cold start the boiler and disconnect the coil. As for the aquastat I'm gonna assume you have an L8124 on there and a knowlegable tech knows how to disable the low limit so's you don't need to buy a new one. BTW, a Beckett Heat manager or similar product will save you quite a few more bucks as well. Google it.

They're saying leave the coil in place, just shut off the cold valve going to it and the hot coming out of it vs taking it out and getting a plate.

And I did ask them about just disabling the low limit on the existing aquastat (I'm not sure which one it is but if it's written on it somewhere I can look) and he said he's seen that done several times and twice it failed after about 6 months but didn't say why. Now I'm wondering if I really should have them do it or what. Anyone from NE PA on here that has a clue and makes house calls?

Yes, leave the coil in place, just shut it off. The low limit is just a switch that makes on temperature drop. There is no reason why disabling it would cause anything to fail. I have disabled a few dozen or more over the years, none have failed because of it.

But not something I could do myself? Just seems silly to spend $277 for part and install (though it's not THAT much in the grand scheme of home maintenance) when what I have is perfectly capable of doing what the new part will.

During the heating season, when the boiler may need to run frequently, you would probably want the low-limit functioning. Once you figure out which wire it is, you could just put a switch on it (toggle switch, wall switch, whatever as it's low-voltage and not much current, most any switch would work), and close it during the heating season, and open it the rest of the year.

oh wow..... well now we're into a whole 'nother realm. new england huh... want to take a nice trip right down 84? i'm 5 minutes off the exit in PA

i'm totally torn on what to do at this point because i can't seem to find anyone down here that can give me a straight answer. anyone know anyone in PA?

Take the cover off, take a good picture and post it and I'll tell you which wire to cut and cap.

Seriously??? I'm going to do that right now. Thanks!!! Is there any merit to the switch thing? (Not doubting Jim but I've heard so many mixed things....)

Ok here you go. (I also noticed the high was set to 170 and low to 150 with a diff of 10 and I'm wondering if that should be 180H and 160L or if it's close enough)

In case anything isn't clear, I jotted down the following notes:
To the L1 screw is the black from the main switch (hot I assume)
To the L2 screw is the white from the main switch
To the B1 push on post is the red from the main switch
There's a yellow wire coming in from the main switch (on the bottom) that is just coiled up and not attached - bad or ok?
The yellow under the H dial goes to YL on the control board - this looks like a permanent connection - not screw or push on
The red under the L dial goes to RD on the control board - also looks like a permanent connection
White from the DIFF dial to WH on the control board - permanent connection
From the push on post top left is a black wire to BK on the board (permanent connection)
From the push on post top right is a blue wire to BL on the board (permanent connection)
Thermostat wires to T and T at top

I'm guessing it's the red under the L dial to RD on the board that needs to get cut (looks like it can't just pull out or unscrew so it's a pretty permanent change) but let me know what you think. I guess it could also be the blue wire (purely based on location related to H and L dials)

Also, if I did want to put said wire to cut on a switch, can I just run wire up out of the box next to the T stat wires and over to a switch somewhere. Not sure where I'd mount that......

thanks!

Hi there. Just wanted to check in on this. I'm thinking it might be the blue wire based on something I read online. Looks like I could just pull it out and then if necessary, put it back in during heating season?

The Blue. Pull it and cap it.

Awesome, thanks! Where can I send cookies??

Good deal, I pulled the wire but left the connector on and electrical taped it off and my husband just took a shower. The boilermate zone called for heat so I ran down and the boiler was down to 120 degrees and then ran until it hit about 145 - 150 when the boilermate zone stopped calling for heat (the boilermate is set at 135 - 140) and it shut off. Good stuff! So if I understand this right, the boiler will only run when a zone calls for it and will shut off when either a.) the zone stops calling for it or b.) it hits the high limit of 180, whichever comes first, right?

I'm reviving this post because when our oil company service guy came out to address my other burner issue (i.e. lockout when it's on its own cold but resets and works just fine and then will fire again fine if it it's still warm), he said that it's not just taking the blue wire off, there's 2 other wires that have to be wire nutted together but he didn't have his manual. There's no truth in that right? I trust the good info I got here but I just want to make sure I'm not missing something and can't see what other 2 wires it would even be.

watson524 said:

cold start and then my eyes glazed over...

Click to expand...

I just googled cold start to find out more about this methodology and found this thread (insert chuckle).... My eyes are so glazed over from my research, ...lol. Though this thread is from back in 2011, I definitely feel ya pain!!