Boiler / T-Stat Questions !!!

Old 12-25-09, 07:28 AM
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Boiler / T-Stat Questions !!!

Hello All

I am trying to optimize my heating system for best
oil economy. First I'll give you some pertinant Info.

House = 1000 sq ft, not very will insulated.
Location = Northeast (New Jersey)
Boiler = oil/Steam/single pipe , 7 radiators (4 down, 3 up)
Beckett AFG burner (2 years old, installed last year).

Let's assume outdoor temp is 30 degrees F and the thermostats
are both set to 66 degrees.

Now the senario. I have tried two different thermostats, one is
an old Hunter programmable the other is a new Honeywell programmable.

With the Hunter the heat will cycle as follows:
64 degrees, call for heat, runs for about 1 hr till temp gets to 68 degrees
then off. Takes about 1 hour for temp to get down to 64 again then repeat.

With the Honeywell, the temp swing is only 2 degrees and the heat will cycle
2 to 3 times an hour.

Now questions !
Is the Honeywell t-stat cycling to often ? What is normal ?
Is the Hunter allowing the boiler to get too cold, thus using
more oil to bring it back up to temp ?

Thanks in advance for your help !
Old 12-25-09, 09:51 AM
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John, before messing with thermostats and such, it might be a good idea if you looked at things like your steam vents, both on the main line, and on the individual rads... and also that the main lines are all well insulated... in other words, make sure that your system is all that it can be first... THEN work on the t'stats.

It could well be that the slow response time is due to some venting issues.

I'm not a steam-head, so hopefully one will be along to further explain.
Old 12-25-09, 02:45 PM
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Thanks Trooper !
I replaced the vents last year along with my best attempt
at balancing the rads. When the temp comes up the rads
all seem to hiss at the same time. My thought is that
if the boiler cycles more the boiler temp would maintain
higher and not let the boiler cool down too much. The thing
is, is 3x per hour too much "on" time and taxing the Beckett ?
Old 12-25-09, 05:47 PM
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Typical steam systems cycle once per hour. You may/should have a cycles per hour (cph) setting on your thermostats. Set them for 1 cph.

A great homeowner book for steam systems is "We Got Steam Heat!" by Dan Holohan. His "Lost Art of Steam Heating" is also excellent.
Old 12-26-09, 08:40 AM
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The keys to efficient steam operation is as Trooper stated, good steam vents and insulation of pipes. Insulate everything in the basement. The real importance is the horizontal main. I also suggest all the rest of the steam piping up to the floors including near boiler piping.
How long are the mains and what size vent do you have as a main line vent. Maybe a second main line vent is in order, depends on the cfm of air required to remove.
Here is a link to FAQ on steam systems.
Steam FAQ

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