How bad...

the_donut

How bad is it for a building to be heated only by mains and risers? I’ve got a building like this. Lead tech wants to leave it this way. Outdoor sensor is used as a wwsd. Indoor sensor isn’t used to regulate building. Boiler runs on pressure under 60 degrees outside. Not sure how to or if I should approach supervisor to get building regulated by indoor sensor.

ratio

...is it comfortable there?

the_donut

Miserable. Better now that all radiator valves have been replaced. I have only seen 1 radiator on out of 100 or so. That room was at least 90*. Shoulder season is miserable there. Used to be 80* with windows open. His argument is owner is saving money compared to before.

My concern with temperature regulation is lack of vents. Not 1 vent. Looks like air comes out of a bfp, which is used as a condensate transfer pump to another bfp in series. My guess is installer sized for 15 minute condensate return, changed some previous wet returns, but still had issues with receiver size.

Jamie Hall

Do I presume that either the lead tech or the building owner also owns the fuel supply company? Not sure I'd even know where to start...

ratio

Ah, the radiators are there, just (mostly) turned off? Well, anything you can do to get the burner off will save money. That should be an easy point to make. I think this is the place for what is it, Heat-Timer? The first case study quoted 10-12% savings, presumably over a previously in-service control system—but you have none. Make the pitch in a hot room.

nicholas bonham-carter

Remember that the heat-timer system has been sold many times as a solution for an unbalanced system, which has not worked, from our experience here. Fix the system first and then decide what type of control to use.—NBC

the_donut

That's my concern. Hard to pitch savings to an owner while saying well, we might have to fix 50 or so traps and possibly remove/replace receivers and pumps.

Currently building is on spending moratorium, pitching a new control device, over a fancy existing Honeywell T775M2048 (programmable for ag/industrial use, looks okay for hot water, not sure why we would use it for steam) from someone with less experience... I am just not sure how to hash it out.

nicholas bonham-carter

Maybe this would be a good use for orifices, whose cost would be less that new trap elements.
On the other hand, maybe the traps are mostly ok, but just unable to work because of high pressure.—NBC

delta T

what pressure is the boiler running at?

ratio

I was thinking that the Heat-Timer would allow you to ease into the repairs. Start at 100%, then slowly turn down the duty cycle and wait. Everything won't be too cool at once, so the repairs could be spread out over as long as necessary.

At least, that's how it was going to work in my mind.

the_donut

Presstrols are set for 0.5 cutin and 1 diff. 0-30 gauge reads between 4 and 7 psi. Pulled the plugs on the water seal and blew out some gunk, but didn’t service the pressuretrol. Now gauge reads between 1.5 and 4 psi.

I want to run the outdoor sensor as a wwsd control, in series with the indoor temp sensor and use the 2nd of 3 pressuretrols as a high low fire control. Lead tech is concerned about partial heating (so am I).

My concern is the building is 200’ side, 4 stories tall and the receiver is sized small that any extended period down time means the only vent is instructed until the boiler calls for water. Haven’t observed this, but have heard complaints during and after wwsd of hammer, which off course go away Monday morning. No setbacks or program on the 775 at this time, just the wwsd and pressure controls.

Mike_Sheppard

Sounds like a hacked up system. Never seen a T775 control a steam system... They do have a model that is capable of reading pressure but it still doesn't offer control over the system like a true steam system control does.

There was this really awesome custom control I saw on LinkedIn built by Duel Fuel Corp. They used wireless temp sensors in each apartment that relayed their temp back to the main control. That control would run the boiler only enough to maintain an average set point temperature between all of the temp sensors. I thought that was pretty neat, rather than going off of cycles.

I think if you want that system to work any kind of right you will need some form of control. Perhaps a less expensive Tekmar. After that I would begin tackling system problems. I know how hard it can be to convince them to fix all of the problems. Had one building where they removed the vacuum system, installed a standard receiver tank, installed three new, oversized, boilers, and installed a "master trap" at the brand new tank because of steam coming back in the returns. System pressure set to 10 psi. I asked them why 10 psi, they said because after the new system was installed with the vacuum pumps removed, the building no longer heated evenly so they jacked the pressure up. I asked if it worked, they said most of the building now overheats, water hammer is terrible, and they "had" to add the master trap to stop steam from reaching the new condensate tank, which it didn't. I tried to explain all of this to them, show them proof, etc, but they didn't want to hear it. They just spent a ton of money on a "new system" now they don't want to spend the money to do it properly.

They didn't want to fix it so there was nothing I could do for them and I moved on. I'd say try to get them to make the system right, or just forget about it and move on to the next one.

nicholas bonham-carter

The problem with any wireless controls in a big building like this one, is coverage of the signal.
When the system was first installed, the heat would have been balanced, even, and economical. Now with lack of maintenance, it’s become a nightmare.
So many special controls have been sold promising to correct situations like this, making conditions worse, and the owners end up here asking for advice.—NBC

Mike_Sheppard

@nicholas bonham-carter I didn’t mean that the control would solve the problem. I just thought it was a neat when I saw it and figured I’d mention it.

My point was, the boiler can’t just run 100% of the time and maintain pressure on the system 100% of the time. From what I understand, he currently has a boiler controlled only by warm weather shut down using a T775. So if it’s less than 60 degrees outside, the boiler is running and maintaining steam pressure on the system non-stop. At 59 degrees outside the system will be heated constantly. No matter how well the system is maintained, that’s going to overheat a system.

I think the first step is to get a proper control in there. Next determine the steam pressure you need, and reduce to that level. Then start to tackle the system problems.

How big is the building? You could try to run the building off of the single indoor sensor, but I’ve never had good luck with those kinds of set ups unless the building was very small. With the T775, you can use multiple indoor sensors wired in parallel-series (consult the manual for details) that allow you to mount them in different areas and they will read an averaged temperature between all of the sensors. Use sensor A as outdoor for WWSD. Use sensor B for indoor. Set relay 1 to reference sensor A, and use that as WWSD. Set relay 2 to reference sensor B, and that will cut your boiler on and off based on indoor temp. Run the burner limit circuit in series through the relays, common and normally open. Perhaps that would be the most cost effective solution for now, and it would be very easy to do.

the_donut

I am thinking about writing up a good/better/best proposal. Good being at least regulating temperature, either via parallel sensors or moving sensor from basement to middle of building. Better being an actual boiler control, 2 stage firing and figuring out the receiver situation. Best being restoring system to a vacuum system.

I talked to a hvac rep about b&g’s vacuum pump and bfp combinations. Hard to find one small enough for a lgb-12. I would prefer it be returned to vacuum to have balanced heating. Supply side is about 40’ of 6”, followed by 20’ of 4” and about 280’ of 1-1/2” and 200’ of 3/4”. Returns are about 600’ of 1/2” that leads to 200’ of 1-1/2” that ends at a bfp used as far as I can understand it as a condensate feed pump for another boiler feed pump. The receiver vent height is about equal to the top of the condensate return pipe. Pipes are pretty old and bfp is in a pit about 6’ below boiler water line. Receiver vent sits about 3’ below bwl.

Steamhead

the_donut said:

..... the receiver is sized small that any extended period down time means the only vent is instructed until the boiler calls for water.

We've run into this. Simply vent the return at the highest point above the tank that you can, so it won't overflow into the room.

the_donut said:

I talked to a hvac rep about b&g’s vacuum pump and bfp combinations. Hard to find one small enough for a lgb-12.

Talk to @Pumpguy if you haven't already. If anyone out there would know, he would.

nicholas bonham-carter

In your letter to them, let them know how much fuel they may be wasting, by having the system constantly on. This is not an old coal burner boiler, which is fired up in the autum, and finally finished in the spring. Where could they have got the idea that this is a proper way to heat a building?
No wonder when they get the fuel bills, they may say, “spend no more on any maintenance”
Probably, the right sort of mindset which we may have is not part of this building management, and you may have to walk away, if they do not agree to do more.—NBC