Thermostat for residential single pipe steam system

skipole

Short version: I need a recommendation for a programmable thermostat (at least 5-2) for my home's single pipe steam boiler. I do not believe I have a C wire. (How can I know for sure?)

Longer version: I apologize because I know this has been asked before. Folks have recommended the Honeywell Vision Pro 8000. When I look on Amazon, there are several different models. When I look at Honeywell's site, there is one model. (If anyone from Honeywell reads this, the usability of your site for a consumer is really poor...). I thought my Honeywell/34 died a while back and I confirmed it today. The program showed that it should be set for 60 degrees but the thermostat thought the set point was 69 degrees.

I also read a lot on this board about cycle times, appropriate differentials to set for steam, etc. Any pointers to reading material in this area would be greatly appreciated. We are out of the house for 9 hours almost day. My house is 110 years old, had no insulation and it gets quite cold on our first floor (where the thermostat is) during the winter. I'd hate to think that we are paying to heat the house for those 9 hours.

Thank you.

Snowmelt

Chances are you don't, is your thermostate hard wired? Most likely you have two wires one red and one white, I would just get a cheap vison pro, they seem to work good.

skipole

Fast reply! Thanks Snowmelt. It is hard wired. If I can avoid it, don't want to take the current thermostat off the wall to see what wires I have until I am ready to replace it.

Is there a table of Vision Pro models and differences? The Honeywell site is pretty useless in this regard. (Or I am useless if I just couldn't find it!)

Mark N

Go to supply house.com, honeywell visionpro thermostats. You don't need any of the wireless models or the 3 heat/2cool models. Get the 1 heat/1 cool model. You also don't need redlink or wifi

skipole

Thank you again. I will look.

Mark N

Good luck, but why would it bother you if the heat ran while you were at work?

skipole

I would think that it would save me money if it didn't. Or at least if it didn't run as much.

Jamie Hall

The VisionPro is the way to go. Battery powered (just don't forget to change them now and then!) and two wire. You can get one with a 5/2 program or a seven day. Most of them have four program slots per group or day. You might consider this one:

http://www.amazon.com/Honeywell-RET97C0D1005-Touchscreen-Programmable-Thermostat/dp/B00B8KNWK6/ref=dp_ob_title_hi

Don't get carried away with the setback feature. Steam doesn't really play well with setbacks; although you will get different opinions, most seem to think around 3 degrees is about right.

And make sure you set it up for steam -- 1 cycle per hour.

BobC

Be careful with deep setbacks with steam heat, it may end up costing you money. That is especially true if you are seeing the temperatures I am. Better to play it safe than risk pipes freezing up.

It has been 10-15 degrees colder than normal around here for the last month, a boatload of snow, and very little sun. I'm retired and on a fixed income, I try to save where I can but I don't pinch pennies in this kind of weather. Then the gas bill comes due I'll grit my teeth and pay it.

Bob

skipole

No deep setbacks that could cause pipes to freeze...

I guess I don't understand the 3 degree recommendation. At one cycle per hour, why not let it drop by 10 degrees for 8 hours when no one is home?

Fred

It will probably take several hours to recover from a 10 degree setback. I would suspect any fuel savings you might get during the day would be gone by the amount of time the boiler will run to recover, especially on cold days. If the boiler is at all over sized for the amount of EDR you have in the radiators, during that recovery, the boiler will probably short cycle any number of times attempting to get the house back up to temp. Radiators can only condense so much steam, converting it to heat.
Typically 3 to 4 degrees is workable and even then, the boiler may short cycle. I ran a 4 degree setback for a couple years and have not run a setback at all over the past 5 to 7 years. In my case, I saw no difference in fuel costs. This has been an on-going topic of discussion on the site but, for the most part, everyone tends to agree., more than a 4 degree setback is not good for a steam system.

KC_Jones

A 10 degree setback in almost any hydronic system is massive. Forced hot error would do that, but not hydronic. Remember you aren't just heating the air (like scorched air does) you are heating every single surface in the whole house to come back from a 10 degree setback. If you could track the difference in boiler on time (NOT CALL FOR HEAT) of one versus the other you would probably be very surprised. 2-4 degrees might be saving, but 10 is probably burning more fuel then no setback. If you research heating degree day and figure out how to run those calculations you could do a comparison of fuel usage from month to month and experiment with 10 degree setback versus no setback. Remember though if you do this you can't change anything else with the system during the experiment or you mess up the comparison. I would also add if you are dropping 10 degrees in 8 hours on a normal day...you need to do some very serious work on your house. I think I would have to leave windows open to drop that much in that time period.

BobC

When temperatures are more normal that might work out but when you get to the bone chilling part of winter you have to be careful.

When it gets really cold with a stiff breeze any air infiltration that finds a pipe with water in it is liable to freeze. The few dollars you saved on fuel will pale against the MANY hundreds of dollars you might have to pay to get that pipe fixed.

When you let the temperature drop that low if anything goes wrong - power, phase of the moon, or just **** luck, you will be introduced to Mr Murphy, When you meet him the first thing you learn is that he holds all the cards.

If power goes out you will be that much closer to having things freeze up - and that includes you. When a storm is coming and they predict high winds with the possibility of power loss I always dial my setback down to half what it might normally be because if power does go out I want a little padding.

The other thing to consider is it takes a lot of energy to move a whole house full of stuff ten degrees, you have to pay for that energy. If your low temp setting were 16 hours it might be worth it - if nothing unexpected goes wrong.

In the long run you will be better off letting the moths out of your wallet and paying the piper. I'll be 68 in a few months and I've seen it all, never assume it can't happen to you. - life is just to short.

Bob

skipole

I just read some of the long thread at http://forum.heatinghelp.com/discussion/152822/is-there-fuel-savings-with-deep-setback-with-steam-heat and understood some of it... Great stuff.

KC_Jones

skipole said:

Great stuff.

You will find a lot of that on this site.

Mark N

Just because the thermostat is set to 1cph doesn't mean it will run once an hour. During the day if it is sunny it may not run much at all because of solar gain. Even down at zero the other day I was running one cycle every 90 minutes.

skipole

The "good" news about my house is that temperatures drop very quickly. 110 year old house with no insulation, gaps that let in the cold, etc.

Maybe I'll spend some time in the basement this weekend to see how often the boiler short cycles when trying to raise the temperature 10 degrees.

skipole

I may also experiment on how long it takes to drop 10 degrees. I realize that the outside temp is a major factor. My assumption was that it was fairly fast in this old house but I could be (and would love to be) proven wrong.

KC_Jones

skipole said:

I may also experiment on how long it takes to drop 10 degrees. I realize that the outside temp is a major factor. My assumption was that it was fairly fast in this old house but I could be (and would love to be) proven wrong.

If you determine you are dropping 10 degrees in a few hours, no matter what the outside temp is. You should seriously consider tightening the house up where you can. For a little money the payback on that effort will be massive. It's not the big things it's the little things. Gaps in the foundation, sealing the rim around the wall perimeter, closing off (with insulation) the bottom of the balloon frame walls. Those things can make a huge difference. Don't look at high dollar windows, doors wall insulation and ignore the other things. They do pay back, but the air infiltration on the old house is a big problem that can be taken care of easily and affordably. You can do all you want with setbacks and heating improvements, but a few hundred bucks sealing the house up some will give you a much bigger bang for the buck than any setback ever will. Just my $0.02 worth.

John Mills_5

Just remember that it isn't just the air in your house cooling 10°, it is everything. Walls, ceiling, flooring, furniture, drapes, beds, everything. So first you have to get the rads steaming hot, then they will start heating the air. Since heat goes to cold, fast as you heat the air, that heat will be drawn to all these cold surfaces and products in your home. So really it will take hours to get everything back up 10°. The house will be comfy about the same time as the stat turns back for your night setback!

Fred

Im guessing this Home owner has been using a 10 degree setback for a long time and probably already knows the issues and is willing to live with them. he initially asked about a new thermostat because his registers 69 when he set it for 60. Probably frozen

jch1

We are getting pretty cold temps here in Chicagoland, and I just checked to see how quickly my house drops in temperatures when it's around 0 degrees outside. My thermostat registers a two degree drop in temperature between 25-30 minutes. I'm sure the rate of temperature drop would decrease, but extrapolating would give me about 4-5 hours for a 10 degree drop. Does this seem too fast? The house is around 90 years old, and I don't know where to start with insulation (plaster walls, mostly original windows, etc.)

Any help would be appreciated.

Abracadabra

jch1 said:

We are getting pretty cold temps here in Chicagoland, and I just checked to see how quickly my house drops in temperatures when it's around 0 degrees outside. My thermostat registers a two degree drop in temperature between 25-30 minutes. I'm sure the rate of temperature drop would decrease, but extrapolating would give me about 4-5 hours for a 10 degree drop. Does this seem too fast? The house is around 90 years old, and I don't know where to start with insulation (plaster walls, mostly original windows, etc.)

Any help would be appreciated.

Check for air infiltration first before you consider insulation. Windows/Doors/recessed can lighting/outlets/switches

KC_Jones

If your basement is unfinished do what I did. I walked around with a can of spray foam and feel for air coming in. Find the source of the air and spray foam the leak closed. It's something cheap and easy that can keep the air out. Some times the little things add up to a lot.

jch1

Thanks guys. Basement is finished, but the biggest problem is windows. On some of them, I can feel a draft rushing in, which leads me to my next questions.

I don't know window terminology, so forgive me, but on some of the windows, the draft is coming in below or outside of the entire frame. Is this a caulking job? On other windows, which appear to be "upgraded" Pella ones, there are huge gaps and/or voids between adjacent windows. I'm guessing to fix this, I would need to find someone to break down the framing to either fix it or insulate it further?

vaporvac

If you use any foam, make sure it is fire-rated! I'd start in the attic and insulate and vapor barrier the floor and any knee walls. It made a humongous difference in my house.

Some of my window molding came off easily, so I insulated, sealed and put it back on. If it's too difficult to remove or will ruin you plaster, Just seal around with a good silicone caulk. That works wonders. Get seal-n-peal for gaps where the windows meet. Again Amazing. I'd make up some interior storms, or buy some good exterior ones but maybe use the plastic hairdryer stuff until that time. Just be aware that the two-sided tape can discolor your wood work if not completely removed in the spring.
This clearly show that new windows may have a higher R value than singl pane WITHOUT storms but do nothing to improve infiltration. Far better to fix what you have and maintain the original beauty of your old-growth windows. It's more ecological and cheaper and storms will give you ~ the same R value.!