baseboard help

[crashingace]

I am second guessing myself right now. I had one of my guys install 2 8' baseboard heaters in a bonus room over a garage. he installed a Honeywell TL7235A1003 non programmable t-stat. The owner is complaining that sometimes the room gets up to 80 and the stat reads 72. I sent my guy back out to look into things and he could not find anything wrong so he just changed the t-stat out. The customer called back and the same thing was happening. I went out with my guy to figure things out. I brought our thermal image with and found that there was a cold draft coming into the box that the t-stat was in. so we spray foamed the box up to keep the draft out. as i was looking around the room i noticed that the baseboard heaters were putting out heat and the t-stat was not calling for heat. so we did a little more investigating. We found that the stat would break both legs when shut off then on a call for heat it would close both legs once the stat was satisfied it would only break one leg?? it is listed as a DPST stat. with one leg at the base board all the time would it put heat out? I would think no as the circuit is not complete without the second leg but how else would there be heat coming out of the baseboard when there is no 240 present?? any help on this matter would be greatly appreciated.

 

[Dennis Alwon]

If there is heat coming out then there is either 240V or 120 V getting to the elements. There is no way it can heat without some voltage. Now it may be that the t-stat is leaking voltage somehow, IDK but those t-stats are also notorious for not being very accurate.

Is the T-stat on an outside wall??? If so that is a bad idea, IMO.

 

[Dennis Alwon]

I would not use that type of t-stat. Get a simple dpst T-stat without the digital stuff. Something must be getting thru

 

[peter d]

I would not use that type of t-stat. Get a simple dpst T-stat without the digital stuff. Something must be getting thru

That's not good advice at all. It is the simple, snap action thermostats that are wildly inaccurate. The digital triac thermostats are generally accurate to a fraction of a degree.

 

[goldstar]

FYI, you should check the rating of thenT-stat. It may not be rated to handle two 8' electric baseboard units. Also, you cannot connect the two 8' units in series. The non-digital T-stats only break one leg of the 240V

 

[ritelec]

That's not good advice at all. It is the simple, snap action thermostats that are wildly inaccurate. The digital triac thermostats are generally accurate to a fraction of a degree.

Maybe if they are working. Personally if the temps alittle off who cares. I also would stear clear of the digital and get something more mechanical as Dennis's suggested

 

[peter d]

Maybe if they are working. Personally if the temps alittle off who cares. I also would stear clear of the digital and get something more mechanical as Dennis's suggested

The problem is that mechanical stats are rarely off by "a little". It's usually 5 degrees or more which is unacceptable in my book.

 

[ritelec]

So turn it up or down that five degrees. Beats dealing with a piece if digital c•ap IMO

 

[sparks1]

Similar problem

Similar problem

I am second guessing myself right now. I had one of my guys install 2 8' baseboard heaters in a bonus room over a garage. he installed a Honeywell TL7235A1003 non programmable t-stat. The owner is complaining that sometimes the room gets up to 80 and the stat reads 72. I sent my guy back out to look into things and he could not find anything wrong so he just changed the t-stat out. The customer called back and the same thing was happening. I went out with my figure things out. I brought our thermal image with and found that there was a cold draft coming into the box that the t-stat was in. so we spray foamed the box up to keep the draft out. as i was looking around the room i noticed that the baseboard heaters were putting out heat and the t-stat was not calling for heat. so we did a little more investigating. Wefound that the stat would break both legs when shut off then on a call for heat it would close both legs once the stat was satisfied it would only break one leg?? iis listed as a DPST stat. with one leg at the base board all the time would it put heat out? I would think no as the circuit is not complete without the second leg but how else would there be heat coming out of the baseboard when there is no 240 present?? any help on this matter would be greatly appreciated.

Is the thermostat controlling a relay?

 

[ritelec]

So turn it up or down that five degrees. Beats dealing with a piece if digital c•ap IMO

Just to ad. If you have a dead on the money tstat that's reading 69.5 degrees that's great. But that t stat might be 15 feet away from you. Where you are could be 3 or 5 degrees different than where the t stat is. You would probably need to play with it to get it ti where you like it any way. Just like playing with the hash marks on the mechanical 2 pole or even the old Honeywell mercury 24v for hot water baseboard or digital programable.

It's still an adjust and feel thing is all I'm saying. So even if the digital is more accurate. I don't think it makes a difference.

 

[texie]

I am second guessing myself right now. I had one of my guys install 2 8' baseboard heaters in a bonus room over a garage. he installed a Honeywell TL7235A1003 non programmable t-stat. The owner is complaining that sometimes the room gets up to 80 and the stat reads 72. I sent my guy back out to look into things and he could not find anything wrong so he just changed the t-stat out. The customer called back and the same thing was happening. I went out with my guy to figure things out. I brought our thermal image with and found that there was a cold draft coming into the box that the t-stat was in. so we spray foamed the box up to keep the draft out. as i was looking around the room i noticed that the baseboard heaters were putting out heat and the t-stat was not calling for heat. so we did a little more investigating. We found that the stat would break both legs when shut off then on a call for heat it would close both legs once the stat was satisfied it would only break one leg?? it is listed as a DPST stat. with one leg at the base board all the time would it put heat out? I would think no as the circuit is not complete without the second leg but how else would there be heat coming out of the baseboard when there is no 240 present?? any help on this matter would be greatly appreciated.

I believe that 'stat is actually Aube (owned by Honeywell) and is probably a solid state proportional control. Note that it is rated for only resistance type load for this reason. The Aube stuff in my experience has always been top notch and it would be my first choice for resistance type heating load.The DPST probably refers to the full off setting. Also as an FYI, if you are using standard 250 watt/foot baseboard heat heaters, 16 feet would be 4000 watts. I think that 'stat is only rated for 3600.

 

[Sierrasparky]

If there is heat coming out then there is either 240V or 120 V getting to the elements. There is no way it can heat without some voltage. Now it may be that the t-stat is leaking voltage somehow, IDK but those t-stats are also notorious for not being very accurate.

Is the T-stat on an outside wall??? If so that is a bad idea, IMO.

There is nothing wrong with those t stats. Don't know whom told you this.

I would not use that type of t-stat. Get a simple dpst T-stat without the digital stuff. Something must be getting thru

To each his own

I believe that 'stat is actually Aube (owned by Honeywell) and is probably a solid state proportional control. Note that it is rated for only resistance type load for this reason. The Aube stuff in my experience has always been top notch and it would be my first choice for resistance type heating load.The DPST probably refers to the full off setting. Also as an FYI, if you are using standard 250 watt/foot baseboard heat heaters, 16 feet would be 4000 watts. I think that 'stat is only rated for 3600.

Right on. That could be the issue. or wired incorrectly .

 

[kwired]

Mechanical thermostats are never completely accurate. I have seen some that will maintain a fairly consistent temperature but it may be 10 degrees different then what the pointer on the dial says. You can't convince a customer that it works when it is 80 degrees in the room when they set it as 70. I liked it better when none of them had an actual temperature on the face and were just marked LO and HI and a few tic marks between. You didn't get complaints with those - they just had to learn where to set them.

A draft around the thermostat location will effect how it operates, especially if it is cold outside air.

Most of these thermostats are rated at least 22 amps. An 8 foot heater will draw 8.3 amps. Two will not be too much for the thermostat though it is pushing a 20 amp circuit a little hard.

Double pole versions do only break one line during operation. This will still stop current flow. If your heater is still heating above set point you either have a fault somewhere (probably have reduced heat if that is the case) or the thermostat is failed/defective and not opening the circuit.

 

[mtfallsmikey]

IMO, the old Honeywell T87F mercury 'stat was the standard, extremely accurate if leveled properly.

 

[kwired]

IMO, the old Honeywell T87F mercury 'stat was the standard, extremely accurate if leveled properly.

Those were not for switching line voltage though. They were a very good low voltage thermostat and one of the most popular ones out there at one time

 

[K8MHZ]

IMO, the old Honeywell T87F mercury 'stat was the standard, extremely accurate if leveled properly.

I replaced one of those with a Honeywell digital. No way was the old merc switch even close to as precise as the new digital. There is enough difference that the digital will actually save the customer money. I found that to be true and would never go back to the old merc stat.

Checking with a digital thermometer not part of the stat, the room temp swings less than a single degree with the digital. A swing of 4 or 5 or more degrees was common with the old merc switch.

 

[kwired]

I replaced one of those with a Honeywell digital. No way was the old merc switch even close to as precise as the new digital. There is enough difference that the digital will actually save the customer money. I found that to be true and would never go back to the old merc stat.

Checking with a digital thermometer not part of the stat, the room temp swings less than a single degree with the digital. A swing of 4 or 5 or more degrees was common with the old merc switch.

Incorrectly set heat anticipator could make them somewhat worthless.

They also came from a time when that kind of temp swing was expected, today we have better insulated and better sealed buildings, higher efficiency and not so oversized furnaces, or other heating methods.