Heat Issue

HeatNovice

I have what I believe you call a hydro system. My upper floor vents only blow out cold air when the temperature is very cold outside about 10 degrees or below. Once temp outside gets to 25 degrees it works fine again. I touched the pipe in the basement that services the upper floor and it’s very warm/hot. I’m available for discussion please. Thank you 

Big Ed_4

need more boiler temp to produce heat at 10* What is high limit now ?

HeatNovice

BE,

I’m sorry, I’m a novice. Can you help me check?

Big Ed_4

What is the reading of the temperature gauge of the boiler ?

HeatNovice

I will take pic tomorrow and post.

Ironman

If the upper floor Air Handling Unit is in the attic, the pipes may be freezing and blocking flow.

HeatNovice

AHU is in attic. Checked in past pipes hot to the touch 

HeatNovice

Jon_blaney

Is there an attic pipe temperature difference when the system is not heating? Is it the same when it is working? One pipe should be cooler that the other. Maybe a pump controller setting issue. Are you new to the house? Could the second floor be locked out in extreme cold?

HeatNovice

JB, Have been in house for several years, this is the 3rd heating season experiencing issue when approx 10 or below. The pipe usually feels hot/very warm when I touch it. I can go back to attic and double check both pipes.

neilc

take a picture while you're up there,
show the pipes as they enter the air handler,
Is there a bypass up there? and is valve throttled? wide open? shut?
and are pipes burning hot / 180* that you can't touch or hold on to?

Jon_blaney

This has been going on since you moved in?

HeatNovice

Nelic-I will take pics and show.

JB- First 5,years all good. Last 3 issues 

neilc

and same questions in the basement,
I'm assuming there is a air handler down there also, and it works, and that your hot water is going there first, cause it's the easier route,
looking for throttling valves , , ,

HeatNovice

HeatNovice

I have 2 other AHU all well. No issues. Only one in attic when very cold doesn’t provide enough heat to 2nd floor. What does acthr

HeatNovice

Throttle valve look like?

neilc

assuming first pic is return pipe,
where is supply?
where is, or is there a, control valve?

throttling valve would be if supply continues/loops to return, and a way to throttle loop flow,
coil supply and return would branch off attic loop (w/control valve)

HeatNovice said:

Throttle valve look like?

simple ball valve(?)

neilc

and are those pipes burning hot?

HVACNUT

That duct system is zoned. All thermostats connected to that air handler are set correctly? Are the dampers working?

HeatNovice

Remember your dealing with a rookie. I don’t have all the answers. The first pic pipe is very warm. There is another pipe on top that is room temp.Valves are in basement at furnace.

HeatNovice

Only when very cold doesn’t work. Now 25 degrees all is fine.

neilc

is "very warm" too hot to hold onto?

neilc

like as hot as the hot pipe coming out of the boiler?

HeatNovice

I can hold it, for quite sometime. Downstairs at furnace can’t touch. Way too hot.

neilc

you are not getting circulation to the attic, or it would be burning hot.
that is just gravity/incidental flow.

can you post pictures of valves at the boiler?
do you see a dedicated pipe in the basement to the attic?
and to the other airhandlers?
are there valves on these lines?
how many circulators down there?
pictures

HeatNovice

Definitely not burning hot. I will take pics very soon and post. Dedicated pipe to 2nd floor. I will show you.

HeatNovice

HeatNovice

The one with the white tag attached services the second floor.

Jamie Hall

No one seems to have mentioned this, but... I would be very suspicious of that pipe freezing, somewhere up in the attic or on its way up or down. It wouldn't take much -- even an inch or two of ice and you'd get no circulation at all. Nor would it necessarily damage the pipe, if it were a short section.

Try this: you mention that once the temperature gets above 25 or so, it seems to work. OK, when you have circulation going up there -- keep it going. Don't let the pump that runs that circuit turn off. If you don't want the heat at times, turn the fan on the air handling unit off -- but leave the circulation going. See if that helps.

neilc

so a circulator to each AH ?
is one of those black? and go to the attic?
and older? and it's not working?
sorry, which one goes to the attic? 1, 2, or 3?
and one more picture of the 3 lines on the other side of the boiler where they come out and any valves or devices there.
also a picture of the device those circs are wired to,

HeatNovice

Thx JH. So if I set thermostat to 68 and all going well, do I have to increase to say 70 when rooms get to 68 so it doesn’t stop?

neilc

working with Jamie's idea,
and my thinking the circ may be bad,
push the heat up to 75 to see if that circ is working,
with the heat turned up,
please go feel that pipe up there again,
it should be burning hot

HeatNovice

#2 goes to attic. Pic with tag. Works when not too cold.

neilc

neilc said:

working with Jamie's idea,
and my thinking the circ may be bad,
push the heat up to 75 to see if that circ is working,
with the heat turned up,
please go feel that pipe up there again,
it should be burning hot

we keep passing missing messages

HeatNovice

I wil do this but will have to “pause” and swing back around. Does this all make sense if everything is working fine at 25 degrees? Could circa still be bad if working at 25 degrees?

neilc

the attic pipe would be boiler hot if the AH was calling, and the circ was working,
was the attic unit calling when you were up there last?
that's why I'ld say push up the thermostat, and check again

HeatNovice

Heat was set at 64 and not calling for additional heat.Will put to 75 and advise. Thank you!!

Jamie Hall

HeatNovice said:

I wil do this but will have to “pause” and swing back around. Does this all make sense if everything is working fine at 25 degrees? Could circa still be bad if working at 25 degrees?

Yes. It is quite possible for it to work splendidly at 25 degrees. Then it shuts off -- perhaps for only 20 minutes -- on a night colder than that, and the pipe freezes. Then you ask for it again -- and nobody's home. In fact, of all the possibilities, that's the one which is really temperature sensitive.

You really are looking for something which is sensitive to the outdoor temperature here. That's the only variable which you report as being closely related.

HeatNovice

As requested, here are a couple of pics of the back of the furnace. Also I touched the pipe thus evening that serves the second floor-the pipe at the basement-very hot. Saturday, I will crank up heat and see if AHU pipe is hot.

neilc

I do not like that mc and loose bushing and 120V wire entering that questionable circulator , , ,
that all needs to be checked out, and corrected and made safe and solid,
and then,
let's see the other end of that circulator electrical, at the controller, preferably with the cover off and showing any indicator lights.