steam thermostat

Vicky

I have a number of problems that I'm chasing down in my 1900 gas-fired, single-pipe steam heated house: short cycling (with a November bill to match), wet steam (all the way up to the third floor), and just for grins, a little bit of hammer.

On the plus side:
•the boiler was professionally tuned last fall, including cleaning the
pig tail
•the cut in is set at 0.5 (to the best of my ability--backed the screw
out all the way then dialed it in until the gauge just registered)
•the differential is set at 1.0
•the vents are 4 yrs old, were cleaned last year and appear to be working
•there is more than 28" between the water line and lowest steam carrying pipe (the dry return)
•and there is more than 24" from the waterline to the header

On the questionable side:
•the piping at the boiler is a bit odd (see pics)
•I may not be able to force the main feed into the right slope away from the boiler to get rid of the hammer
•I've also noticed that the boiler quits before any pressure reads in
the gauge (so perhaps wet steam is not the cause of short cycling...)
•I've discovered that the thermostat I have is not designed for steam (it's a Honeywell MagicStat/32). The manual states:
"This thermostat does not have a setting for steam/gravity air. Cycles would not be long enough for accurate temperature control."

Before I resort to drastic measures such as re-piping it seems like
the thermostat is a good place to start.
Can anyone recommend a programmable thermostat for steam?

And with regard to the hammer, if i can't get the main feed to slope enough is there another solution?

Thanks.

BillW@honeywell

Steam t'stat...

Using setback on one-pipe steam systems is controversial, due to the "flywheel" effect of that type of heating system. I would recommend that you replace the retail model stat that you have, which is not compatible with steam, since it can't be set to 1 cycle per hour. If you'd like a programmable, try the new VisionPro, or if you want a non-programmable, try the new FocusPro. Either can be set to 1 CPH, and being battery-powered, they avoid the compatibility issues that the older style powerstealing units had with some steam systems.

These are available from any Honeywell distributor, or your local heating pro.

Vicky

steam thermostat

Hi Bill,

I've spoken to one plumber and two supply houses none of whom have heard of a thermostat being incompatible with steam. Can you recommend a programmable other than the vision pro? I'd rather not have that big screen (if I could I'd go with the digital bell, but it's not programmable).

Also could you fill me in a bit more about "setback" and CPH?

Thanks.