Problem with Honeywell 3600

Glenn Harrison

Every once in a while I accidently know what I'm doing. I have found that the 3 cycles per hour works well for everything. This provides approximatley a 10 minute on-10 minute off cycle which keeps all systems running comfortably, and keeps excessive cycling of components down to a minimum. Also prevents condensation from short cycling equipment, as opposed to 6 cycles per hour. Plus look at i this way, one cycle per hour means that equipment will run for 30 minutes and off for 30 minutes approximately.That sounds like to much run time to me. Just my opinion.

Happy Steam Heating

Drod

Honeywell Programmable 3600

Still having a problem with my new, Honeywell Programmable. All settings (single pipe steam) have been set correctly. If I keep the temperature setting at one constant temp., the system works just fine. But, if I use the set back and the Smart Response Feature, there's a problem when the morning temperature ramp up kicks in-it overshoots the temperature significantly. This is the case even after 4-5 days of history and learning by the smart t-stat.
For example: If my sleep temp is set at 68 degrees, and my wake up temp is set to 69 degrees, the house (and t stat shows this) heats up to 71 or 72 degrees at wake up. It always overshoots at the initial ramp up. It's almost like there's no funcitoning anticipator, but I know that's not the case because it works fine after that.
Any thoughts?

BillW@honeywell

Overshoot

Did you set the number of cycles per hour to 1 CPH? If not, please do so. See your instruction manual for how to do it.

Drod

Bill,
Yes, I did set it for the 1 CPH setting. Any other ideas?
Thanks,
Dale

Boilerpro

This is a common problem, I've seen...

What I have found is the problem is that the radiation is much too large for the heat load. I seen this problem on both steam and converted gravity water. The thermostat turns on the boiler to begin warmup, system heats up, rads get hot all the way across, themostat reaches setpoint and turns off the boiler. However, the rads continue to heat the space after the boiler is off and when they are greatly oversized, it can cause serious overheating. I would check to make sure that you are running only about 2 lbs max pressure at most. For one pipe steam, the only solutions I see is downsize the rads or to reduce the boiler size close to the heat load and balance the system with adjustable rad vents. This second solution, however, is not supported by most of the folks here. I'm a bit of a renegade on this idea along with a few others.

Boilerpro

David Efflandt

Similar 3500 works fine for me

I am using similar CT3500 which is 5-1-1 and missing some features of 3600, but works fine for my single pipe steam and rarely overshoots 1 degree (if weather turns milder).

I assume you have the 3600 set for System type of "Gravity or steam" and your Pressurtrol is set as low as it goes.

I use more setback, so I really would not notice if it overshot a bit while ramping up because it ends up where it is supposed to be at the set time. Morning 68, day 62, evening 67 and night 64. The radiator at thermostat (central dining room) is oversize, but boxed in and slowly vented. During ramp up it probably vents more completely, throws more heat, but gradually since it is completely covered except for front grill. All other radiators are smaller.

It works much better than the Robertshaw thermostat my house came with. It always dropped a degree before kicking on, then overshot by at least 2 during any operation (no anticipator or system type setting except Gas/Electric switch).

David Efflandt

Similar 3500 works fine for me

I am using similar CT3500 which is 5-1-1 and missing some features of 3600, but works fine for my single pipe steam and rarely overshoots 1 degree (if weather turns milder).

I assume you have the 3600 set for System type of "Gravity or steam" and your Pressurtrol is set as low as it goes.

I use more setback, so I really would not notice if it overshot a bit while ramping up because it ends up where it is supposed to be at the set time. Morning 68, day 62, evening 67 and night 64. The radiator at thermostat (central dining room) is oversize, but boxed in and slowly vented. During ramp up it probably vents more completely, throws more heat, but gradually since it is completely covered except for front grill. All other radiators are smaller.

It works much better than the Robertshaw thermostat my house came with. It always dropped a degree before kicking on, then overshot by at least 2 during any operation (no anticipator or system type setting except Gas/Electric switch).

Glenn Harrison

Cycle rate settings

> Bill, Yes, I did set it for the 1 CPH setting.

> Any other ideas? Thanks, Dale

Glenn Harrison

Cycle rate settings

Here's a suggestion. Try setting the t-stat to 3 cycles per hour. This should cause the t-stat to cycle off sooner and cut back on overshoot due to the thermostat knowing it needs to cycle more. More cycles should equal less run time per cycle. Try it out, it might just work.

Boilerpro

The Honeywell stats seem to be much more friendly for hydronics.

Drod

Thanks

You know, I thought about that (setting t-stat for 2 or 3 cycles per hour) and with my limited knowledge dismissed it because I always read here that "longer cycles are better". I'm going to try it and see what happens. Thanks

Drod

Glenn Harrison's Solution worked!!!!!

and it was: "Here's a suggestion. Try setting the t-stat to 3 cycles per hour. This should cause the t-stat to cycle off sooner and cut back on overshoot due to the thermostat knowing it needs to cycle more. More cycles should equal less run time per cycle. Try it out, it might just work."

Even the Honeywell experts and help line people never came up with a solution. Thanks!

BillW@honeywell

Sorry about not following up...

I've been away from the "Wall" for a couple days, but it looks like you got some good advice. The 1 cph setting is what is "recommended" for most steam systems, but the others are absolutely correct about the way your particular system works. I apologize if you got the runaround at the helpline.

Drod

Bill,
I did not get the run around at all, they made several suggestions and were very courteous and responsive-they did a good job. Unfortunately their suggestions didn't work, and Glenn's did. I suspect you would have come up with the same suggestion too. I'm such a novice at this that I was pretty "hell bent" on not changing from the one cycle per hour/steam setting because of what I'd traditionally read on the threads here.
Do you think I'll use much more fuel with the new cycle setting? I kind of doubt it.
Thanks for your respnses.

BillW@honeywell

I'm glad they tried to help

Thanks! I'm glad to see they were helpful. Steam systems are individualistic beasts and not all generalized settings are right for every application. Thanks for using Honeywell products.