upstairs too hot because of hydronic heat?

Ray Landry

A thermostatic valve would work well on the 1st floor rads, if you were trying to have different room temps on the zones.. I think you're confused in what the valve actually does... it wouldn't 'conflict' with the t stat.

Is your basement ceiling finshed/insulated? Slapping up some insulation would keep the heat in the first floor better and not cause the boiler to play catch up w/ the massive heat loss of the (to my knowladge) uninsulated floor. This would mean less heat traveling upstairs to the overheated bedrooms...

R. Kalia

hydronic heat = upstairs too hot?

Our 2nd fl bedrooms are too hot even with radiators off. (Radiator shutoff valves don't leak.) Thermostat is on 1st floor and is controlling the temp there just fine. Even after an all-night setback, in the morning the bedrooms are still 70F while downstairs is 63F (thermostat setting).

Our last house, which had forced air, didn't have this problem. I know there are many variables, but I was wondering if the likely culprit is lack of air recirculation (in forced air system, warm air is pulled down by the returns, so it doesn't all pool on the 2nd fl). We do have a wide, open (no doors) stairway.

Is my theory reasonable? Could there be other reasons? Is there anything to be done other than move (or install a forced-air system)?

Dale

Rads hot?

If your upstairs rads are indeed the same as air temp you have a house that is really well insulated. With an open house plan and a well insulated space keeping one area at 60 while the other stays at 70 may be hard. What you could try is to lower the temperature of the boiler water first, this is cheap. Perhaps an aquastat setting of 150 instead of 180 will be all you need, if that doesn't work then some sort of thermostatic radiator valve for the downstairs that you can adjust so there's no overshoot. An air leak upstairs can also draw warm air up, make sure your attic access is sealed and the windows upstairs kept closed.

Mike T., Swampeast MO

Forced-air heat = downstairs too hot?

Before you blame the radiators remember that the subject line could well have been true with the forced air but such was actually to you liking...

Please clarify a bit.

Is the upstairs ALWAYS too hot or just staying significantly warmer than the downstairs when you've set back the thermostat?

R. Kalia

reply

> If your upstairs rads are indeed the same as air

> temp you have a house that is really well

> insulated. With an open house plan and a well

> insulated space keeping one area at 60 while the

> other stays at 70 may be hard.


I'm not trying to do this. I am trying to get the bedrooms to be the same temperature as downstairs.

> is to lower the temperature of the boiler water

> first, this is cheap. Perhaps an aquastat setting

> of 150 instead of 180 will be all you need, if

> that doesn't work then some sort of thermostatic

> radiator valve for the downstairs that you can

> adjust so there's no overshoot.


One can't use thermostatic valves in space controlled by the thermostat; the two would conflict. Anyway there's no overshoot on the first floor in this cold weather, although indeed there is some in warmer weather.

> An air leak upstairs can also draw warm air up, make sure

> your attic access is sealed and the windows

> upstairs kept closed.




Yes, this makes sense and I'll look for such a leak.

R. Kalia

always

> Before you blame the radiators remember that the

> subject line could well have been true with the

> forced air but such was actually to you

> liking...


Well, the thermostat is downstairs. So I have control over the downstairs temperature.

> Is the upstairs ALWAYS too hot or just staying

> significantly warmer than the downstairs when

> you've set back the thermostat?



It is always a couple of degrees warmer, but the difference increases during setback periods. I am not sure what this means.

Joe_13

Ghost flow?

If the whole house has one thermostat, there's usually a split loop with a set of valves comming off the supply piping from the boiler before the piping heads off to the rads. One for the 1st flr and the other for the 2nd. You might want to test shutting one valve off at a time to see if the circulation will stop to each floor. You could trottle the watter down to the 2nd flr. Sometimes even though the circ pump is off, the hot water in the boiler rises naturally to the highest point. You may have had a converted gravity system which originaly did not use pumps.
In this case you may need a pro to install flow check valves to stop the flow of hot water unless the circ pump is on. You may want to also see if you could put the 2nd flr on a seperate zone with it's own thermostat for better control.

R. Kalia

radiators are cold

We do have a converted gravity system. However, the upstairs radiators are cold when the shutoff valves are closed (and we do keep them closed).

Mike T., Swampeast MO

If it's an old house with iron rads the system was likely installed when there was little (if any) insulation. The upstairs had significantly more heat loss than the downstairs and the radiators were sized correspondingly. This is because the majority of heat loss in a structure occurs through the ceiling.

Likely you've added ceiling/roof insulation--good. BUT, particularly as it gets really cold outside, the upstairs rads become more and more oversized as the heat loss through the ceiling is greatly diminished. Especially if the walls of the old house are uninsulated you'll wind up with the downstairs cooling more rapidly than the upstairs--again most notable during extremely cold weather.

[This may well have something to do with the rash of "too hot upstairs" complaints that have been coming to The Wall in the recent spell of extreme cold in the NE.]

Again is the upstairs ALWAYS too hot? Is it only too hot during really cold weather? Is it just staying warmer than the downstairs when you set back the thermostat downstairs?

Joe_13

Strange

The heat loss downstairs much be so great that the convecting heat is overheating the 2nd flr with all the rads off. You would probably have the same (or worse) condition with hot air since you would be pressurizing the space. Ceiling fans on high ceilings could help force hot air back downstairs. Converting the first floor to radiant heating would help cut down on convection. Long low rise panel rads running at a cooler temp would probably be better then a tall cast iron rad @ 200 degrees. There are cases where oversized baseboard covering all the outside walls running at a lower temp would help to warm the walls and better balance the heating in the space. As Mike said, if this condition is only a problem durring this deep cold spell, then there's an insulation issue with the first flr. Requiring too much heat to match the heat loss, with some of that extra heat migrating upstairs.

[Deleted User]

you may also want to see this thread

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=13211&mc=20#Message78202

R. Kalia

yes...

> Likely you've

> added ceiling/roof insulation--good. BUT,

> particularly as it gets really cold outside, the

> upstairs rads become more and more oversized as


Good catch, not only is the ceiling insulated, but the sides are vinyl on 2nd floor but brick on 1st, and under the vinyl is insulation while brick is not insulated. (We're new in the house so I don't know when it was done, but no doubt it is not original.)

Of course, however oversized the upstairs rads may be, they are turned off so that doesn't matter.

It still makes sense that the upstairs is holding the convected heat in better than the downstairs is holding the heat from the radiator in. That is why the problem is worst at the end of a setback period---I'm seeing the effects of heat losses with no fresh heat being supplied, so insulation is a likely culprit. Thanks!

(I'll also look into whether ceiling leaks are causing warm air to move upwards faster than otherwise.)

Steve Ebels

I'll make a bet

That reducing your water temperature (start at an aquastat setting of 160* and work down) will eliminate your problem. What's likely happening is that the high water temp (180*+?) is creating such a strong convective airflow that your heat is "pooling" at the top of the house. The hot air is rising and the cool air from upstairs is "falling" down the stairway. (You can prove this by holding a match or lighter at the top of the upstairs door casing and at the floor level) Watch what way the flame goes.

If you reduce the surface temp of your rads to the point that they just heat the space on a design day, that convective flow will be nearly eliminated because the air will cool before it migrates to the upper level. At that point you will need to run both upper and main levels to maintain desired temp. Matching the output of the rads to the heatloss of the house is what outdoor reset is all about.

I'll also wager that if you were to do a calculated heat loss and figure the EDR of your rads, they would prove to be significantly oversized. Remember that these old girls were designed and installed by people who slept with windows open for health reasons. Also, think about the structural improvements made to the home since those rads were installed. Windows, weatherstripping, doors, insulation have all likely been improved since the house was built.

Mike T., Swampeast MO

Presuming here that even with the valves shut the rads are still staying warmer than the air...

Radiator hand valves have little holes in them to allow a bit of water to flow and hopefully prevent freeze-ups when the valve is "closed". When the gravity system was converted to forced circulation a surprising amount of water will still flow through that little hole--and it likely enlarges a bit over time...

TRVs on all radiators will bring back balance and allow you to keep each room at a different temperature regardless of the rest. If this is too expensive, you can put them on the rads in overheating spaces only and restore a very good measure of balance to the system. HOWEVER, the upstairs will likely still cool more slowly than the downstairs as the radiators themselves hold a large amount of potential heat when the circulation stops.

R. Kalia

different temps?

> A thermostatic valve would work well on the 1st

> floor rads, if you were trying to have different

> room temps on the zones.. I think you're confused

> in what the valve actually does... it wouldn't

> 'conflict' with the t stat.


Who says I want to have different temperatures in the zones?

A thermostatic valve turns the flow to the radiator down and finally off as the temperature approaches the set temperature. If the valve is set lower than the thermostat in the same room, the thermostat will find that the room never gets to the set temperature. Thus it will keep the heat on all the time, causing all other rooms to get very hot. If the thermostatic valve is set at a temp higher than the thermostat in the same room, it never closes and has no role at all. That's what I meant by 'conflict'.

> Is your basement

> ceiling finshed/insulated? Slapping up some

> insulation would keep the heat in the first floor

> better and not cause the boiler to play catch up

> w/ the massive heat loss of the (to my knowladge)

> uninsulated floor. This would mean less heat

> traveling upstairs to the overheated bedrooms...



Yes, this is a good idea.

Mike T., Swampeast MO

Gravity System Hand Valves

Just conducted a simple "blow" test on one my by old valves. Even in the fully closed position they offer VERY little resistance and I could easily blow through it.

Since they only had to regulate the EXTREMELY gentle circulation caused by gravity they didn't need to be made tight. With a circulating pump they're likely never even close to "off". As I recall (before I added the TRVs) the position of the valves had VERY little effect on the temperature of the radiators.

R. Kalia

Thanks. Certainly we have too much radiator capacity as you guessed. I've heard about outdoor reset, but I'll try turning the water temperature down manually. Not today, though, it's too cold to take any risks.

Mike T., Swampeast MO

I'm not sure, but modern water radiator valves might be much better at actually regulating flow in a forced system. Judging by the price I've had to pay for angle unions though (special order around here) the cost of such wouldn't be much less than that of TRVs and installation labor would be identical. If cost is limiting factor you could delay the purchase of the TRV actuators and use the little manual adjustment provided to regulate flow until the thermostatic actuators are added. The actuators are extremely easy to install and you shouldn't even need a service call.

Ray Landry

Just in case I didn't know how a thermostatic valve works...

'Who says I want to have different temperatures in the zones?'

That's why I said
'A t-static valve would work well on the 1st
floor rads, IF you were trying to have different
room temps on the zones!'

And you wouldn't always need a bypass, especially if you have an old gravity system with a feed and return for each radiator. I've put in many systems that utilize t static valves as well as a t stat. It provides room by room comfort. I wasn't trying to suggest it for your application, just trying to provide info because from what I got from your response, it seemed like you thought the two could not be mixed...

Ray Landry

Just in case I didn't know how a thermostatic valve works...

'Who says I want to have different temperatures in the zones?'

That's why I said
'A t-static valve would work well on the 1st
floor rads, IF you were trying to have different
room temps on the zones!'

And you wouldn't always need a bypass, especially if you have an old gravity system with a feed and return for each radiator. I've put in many systems that utilize t static valves as well as a t stat. It provides room by room comfort. I wasn't trying to suggest it for your application, just trying to provide info because from what I got from your response, it seemed like you thought the two could not be mixed...