Short Cycling Utica Boiler

Steam_Guy56

I bought an old house built around the turn of the century in pennsylvania last January with 1 pipe steam heat. When I moved in only one radiator directly above the boiler was getting steam. After a couple months of being extremely cold, I installed new variavalve vents on all the radiators. This seemed to help a little, but on one cold April day when I cranked the thermostat up to 65 the boiler quit working.
However, as summer approached, I stopped worrying about the boiler and started looking at the AC.
Come October, after inspecting the boiler and clearing out the vent pipe (chimney was not capped), I found that the exhaust thermosensor was tripped and reset it. Once I reset it, the boiler seemed to be running smoothly and heating all of the radiators. After about a month of smooth operation, I started to notice a few of the radiator supply valves were leaking. I replaced 3 valves and repacked the rest of them, and that stopped the hissing. However, around the same time the boiler began short cycling (fires for about 2 minutes, off for 2 minutes). The boiler came with the classic honeywell 404a pressuretrol, which probably never worked since installation correctly. To fix this, I ordered a vaporstat and 0-3psi gauge to see what the actual pressure in the system was. I installed the pressure gauge, but still need more parts for the vaporstat because the factory installed location is too small to fit the larger unit. I found that boiler is shutting off well below the 3psi cutin I have the pressuretrol set to. It’s not evening making 1/4lb of pressure before shutting off. 

Long story short, I believe the cycleguard 400 series low water cut off is shutting off the boiler. I have cleaned the probe, but I don’t know what else to do to fix it besides draining and cleaning the boiler. Any suggestions?
Attached are pictures of the boiler, its backplate info, and the cycleguard info  the

pedmec

your boiler needs to be repiped. installed per manufacturers specifications and best piping practices and all your problems will go away. open up the owners manual and you will see the proper piping schematic.

realliveplumber

Yeah, unfortunately another jack leg installation by someone who had no idea what they were doing.

Get the near boiler piping installed the way the boiler manufacturers manual recommends, and everything will work just fine.

Steam_Guy56

realliveplumber said:

Yeah, unfortunately another jack leg installation by someone who had no idea what they were doing. Get the near boiler piping installed the way the boiler manufacturers manual recommends, and everything will work just fine.

I concur. There’s no hartford loop. No skimport.  They just connected one header with one main and the other with another one and called it a day. 

I was wondering though if you guys have ever seen this kind of low water cut off causing a boiler to short cycle. As far as I know there’s only a couple things to shut the boiler down: thermostat (nope, still calling for heat), the pressuretrol (very much not calibrated, but not  tripping), the thermal sensors (checked them, but the boiler wouldn’t start if they had tripped), or the low water cut off. Anything else I’m missing that could be short cycling it?

109A_5

Hello @Steam_Guy56,
Since there is no equalizer pipe and there is a check valve, maybe the check valve is stuck open so the boiler pressure pushes some of the water back out into the wet returns. If piped correctly you probably would not need the check valve.

ethicalpaul

Are you seeing the water level drop during firing?

if so, this is simply “surging”, or the boiler throwing gallons of water into your main.

a common problem especially with this kind of boiler when it’s improperly piped.

and I have to correct you, the headers are not connected to the mains. There is no header. That’s how bad this piping is. Each steam outlet is piped directly to a main

Steam_Guy56

109A_5 said:

Hello @Steam_Guy56, Since there is no equalizer pipe and there is a check valve, maybe the check valve is stuck open so the boiler pressure pushes some of the water back out into the wet returns. If piped correctly you probably would not need the check valve. 

Good catch on the check valve. I believe it is stuck open, since when i drain the wet return pipes, boiler is also drained. But, I don’t think it matters since the boiler isn’t making even an ounce of pressure now. 

The low water light isn’t actually being activated when the boiler shuts off. So, there must be some timer circuit that is cutting off the burner after about 2 minutes. 

Steam_Guy56

ethicalpaul said:

Are you seeing the water level drop during firing?

if so, this is simply “surging”, or the boiler throwing gallons of water into your main.

a common problem especially with this kind of boiler when it’s improperly piped.

and I have to correct you, the headers are not connected to the mains. There is no header. That’s how bad this piping is. Each steam outlet is piped directly to a main

Thanks for the header correction. Check out this video on the boiler firing. https://youtu.be/J3Iq-S9GCrM

The water level is bouncing a little, but I wouldn’t have called it surging. Is that what this is?
I cleaned out the sight glass valves a couple weeks ago, so they should be telling the truth about the water level. 

ethicalpaul

No, I don't think that's surging. The water level is staying above the probe and as you said above, the low water light isn't coming on, so it's not shutting down due to that apparently.

The cyclegard does interrupt the firing cycle to test the water level, but it's not as often as every two minutes.

It's unclear to me if you are seeing it shut down every two minutes, or did you just see it shut down once two minutes after a firing cycle started? If it is shutting down every 2 minutes, it's probably something else.

The cyclegard's model number tells you how often it tests-- a Model 2060, for example shuts down every 20 minutes for 60 seconds.

When the test occurs is not usually tied to the start time of the firing cycle (although there is a wiring configuration you can use that does reset the test timer at cycle start).

If you are just seeing it every so often, like every 15 or 20 minutes, don't worry about it. Let it test your water level.

ethicalpaul

The lack of an equalizer does not necessitate the presence of a check valve, since the equalizer does not serve the purpose of equalizing pressure in an operating system.

SteamingatMohawk

You said, "I installed new variavalve vents on all the radiators".

In addition to all the needed work at the boiler, you should realize the Heat Timer Varivalves have much greater venting capacity than the individual radiator vents. At the "SHUT' position they vent at the rate of a #5 and almost 6 times that at fully open.

Determine the setting of each valve and "explore" the following report for information.

https://www.heatinghelp.com/systems-help-center/balancing-steam-systems-using-a-vent-capacity-chart/

Steam_Guy56

ethicalpaul said:

No, I don't think that's surging. The water level is staying above the probe and as you said above, the low water light isn't coming on, so it's not shutting down due to that apparently. The cyclegard does interrupt the firing cycle to test the water level, but it's not as often as every two minutes. It's unclear to me if you are seeing it shut down every two minutes, or did you just see it shut down once two minutes after a firing cycle started? If it is shutting down every 2 minutes, it's probably something else. The cyclegard's model number tells you how often it tests-- a Model 2060, for example shuts down every 20 minutes for 60 seconds. When the test occurs is not usually tied to the start time of the firing cycle (although there is a wiring configuration you can use that does reset the test timer at cycle start). If you are just seeing it every so often, like every 15 or 20 minutes, don't worry about it. Let it test your water level.

It is a 2090 model which is supposed to test the level every 20 minutes. The video starts about 15 seconds after the boiler started firing, and it fired back up again a couple minutes later. It fires about 15-18 times every hour. 

ethicalpaul

Well you can jump out the LWCO to test to see if that is what is stopping it, but for love of all that is holy, DO NOT LEAVE THE BOILER'S PRESENCE WHILE THE JUMPER IS IN PLACE

You can do the same with the Pressuretrol, and indeed the thermostat or whatever mechanism is asking for heat.

EBEBRATT-Ed

Yes, follow @ethicalpaul advise then you will know for sure what is shutting it down.

Just take the warning seriously. Don't go answer the phone or leave the boiler with any jumpers in place.

Steam_Guy56

Update: I got the nipples and elbow I needed to install the vaporstat with enough clearance, so I did that tonight. As I anticipated, after I installed it (pigtail was a little dirty but clear) there was still no change to the short cycle. 

I then took a look at the wiring for all the connections to the control module and cycle guard and they seemed secure. 

I unplugged the cycle guard and put a jumper into the harness, and it’s still short cycling. 
My last guess is that my ancient honeywell mercury thermostat is going bad. I will put another update in after I’m done experimenting with that. 

bburd

I cannot imagine a Honeywell mercury thermostat "going bad" unless it has been physically abused. I suggest you make sure it's level, and check the setting of the heat anticipator which needs to be on the long side (higher numbers) for steam.

Is there anything near the thermostat that might make it shut off prematurely? A steam pipe in the wall behind? A quickly vented radiator nearby?

Steam_Guy56

I pushed the brass pointing arm further up the scale. Not sure if thatbis the heat anticipator. 

bburd

Yes, that is the heat anticipator. And you may find it needs to be set a bit higher than that.

AlanBrase

With the cover off the thermostat, it is easy enough to see if the mercury bulb is tipping indicating satisfied heat call.

JUGHNE

I have seen that model of tstat with a shorted heat anticipator.
It would produce so much heat in the tstat that the bulb would move to off position.

After cooling it would go back to on....every few minutes cycling like that.

It may have a separate 24 volt circuit to just run the clock motor, do not short that out.
You can jumper the red and white, R & W to keep the boiler on if you have this problem.

Steam_Guy56

Thanks for all the help about the thermostat. I adjusted the heat anticipator up a little a turned the temperature on the thermostat up to 78 degrees, and now the short cycling problem has seemed to stop. The thermostat is in the kitchen butler’s pantry which had its radiator removed years ago. I’m thinking the  calibration of the thermostat is off or I need to re level it. Either way. It might be time to replace it with the honeywell t5 I have sitting in my desk drawer. 

Back to the near boiler piping fiasco. If any of you guys know a reputable boilerman in the Harrisburg area, I would appreciate any leads. One company I am not going to call is the one who put their sticker on it. 

JUGHNE

Does the HW T5 have an adjustment for cycles per hour, needed for steam operation.
1 to 2 per hour.

PC7060

realliveplumber said:

Yeah, unfortunately another jack leg installation by someone who had no idea what they were doing.

And would never consider reading the manufacturer I&O manual.