I have an older Janitrol boiler, probably the original one installed when my house was built in the 1950's, that I've been having some issues with. I turned the heat on a few weeks ago, and everything fired up as it should. A heat wave came through, and I turned the thermostat all the way down to turn off my heat, and the boiler and heat continued to fire. I ended up turning off the boiler at the kill switch attached to the boiler. When it started to cool off again, I turned the switch back on, and nothing happened with the boiler. Tried cycling the thermostats up and down, and still nothing.

Shortly after this happened, the snow storm that came through New England left me without power for a few days. When it finally came back on, the boiler fired up, but had the same issue as before with the boiler continuing to fire, even when the temperature was well over 10-degrees higher than the temperature set on the thermostat. I started to trace the wires back from the thermostat to see if there was anything wrong, and when I took the gas valve cover off to see if there was anything wrong in there, the boiler turned off. Now I'm in the same position as I was before, with my boiler refusing to turn on. I snagged a multimeter from work, and when bridging the "Transformer" and "Valve" terminals on valve electronics, I only get 20v. I know at least one of my thermostat's is working, because my second heating zone is forced water, and that pump fires on and off as it should when I jog the thermostat. I'm not sure what the next step would be in getting this bad larry to turn on again.

 

Need a little clarification...

You have multiple zones... how many?

Does each zone have it's own pump?

You say the second zone is turning the pump on and off, but don't say whether or not the boiler is firing for that zone. Is it?

Are there 'relay boxes' that the thermostats connect to?

Do you have a digital camera?

 

Sorry, I knew I'd forget to put some relevant info...

There are 2 zones, one steam feeding radiators, and the other forced hot water feeding baseboard heaters. Only the forced hot water has a pump. Both thermostats are connected to a zone-relay, but I don't know the model number off the top of my head. They're also both connected to a pressure switch.

The boiler doesn't fire up for anything right now, I don't have a digital camera, but I may be able to snag one from work and get some pictures up later.

 

Ohhhhh... STEAM!

Your symptoms could very well be that you simply have a clogged pigtail (siphon tube) on the Pressuretrol control.

Either remove and clean the tube, or replace it and I betcha you be back in business pronto.

 

So, I got the pigtail off, and the thing was spotless, put 'er back on, and I'm still only getting 20V (20.5 to be exact) at the gas valve.

Any other suggestions?

 

You could blow through the pigtail?

Just to make sure we're talking about the same thing, you have a Pressurtrol controller on your boiler, YES?

And that control is mounted on top of a pipe bent in a circle... and that's the thing you cleaned?

And while we're at it, what are the settings on the Pressurtrol control?

Don't worry about the 20V for now... that should be enough to operate the valve... the symptoms you describe lean toward that not being the problem.

 

Can you get us the model of the relay?

You say both thermostats are connected to it... what else is connected to it?

And how are the thermostats connected to the pressure switch?

Does bad Larry have a model number on him?

 

Yes, the thing you described is what I took off and checked. I could easily blow through it, and ran a wire brush through it just to be safe. It's an old Honeywell pa404a that has a "cut in" of ~5 psi. I haven't adjusted the thing since I moved in.

Aside from the pressuretrol and the Erie Boiler Boss Relay, the only electronic control attached to the boiler is the aquastat. Also, other than the circulator pump, power, and thermostats, the only other thing connected to the relay is the low water cutoff.

The janitrol panel is pretty ground up, but I think the model is Vi55A-RL. The i may very well have been a 1. I can read the size as JCI-150-64, though.

 

Is that 5 as in FIVE ? Please confirm...

What is the 'differential' setting (inside the 404 cover) ?

 

Aside from the settings, if the boiler fires and doesn't stop, and the siphon tube is clear, it's very possible that the 404 control is 'flaky', and hanging in an on position.

Your pressurtrol settings may be way too high ... but we'll get to that later.

What model is the Boiler Boss ? SR100 ?

http://source.invensysibs.com/litera.../F-27018-2.pdf

The pump for the baseboard water zone is connected to the boiler boss, as is the thermostat for that zone... is this correct so far?

and there are wires from the boiler boss going to the aquastat on the boiler, correct?

The thermostat for the steam zone, where is that wired to ? the pressurtrol?

 

Yes, it is set to five psi

 

That would be the relay model I have. Yeah, the pump and thermostat are connected to the relay, as is the aquastat.

The thermostat for the steam zone goes to a light switch, which then goes to the gas valve, and the switch is connected to the pressuretrol.

 

Need to know this............

 

Oh, sorry, it's somewhere between 1 and 2. Let's call it 1.3

 

If it were my system, I would certainly try decreasing the Cut-In to ONE HALF PSI ( 0.5 PSI ) and set the DIFF to ONE AND A HALF ( 1.5 PSI ).

VERY VERY RARELY do residential steam systems need that kind of pressure to operate! If you NEED more pressure in order to heat the home, it's highly likely that something else is wrong... such as defective steam vents.

The higher the pressure, the MORE FUEL you NEEDLESSLY burn.

With the settings you have, the pressure has to go to the setpoint ( 5 ) PLUS the DIFF ( 1.3 ) = 6.3 PSI before the burner cuts off. Then, the pressure has to drop to the setpoint before it cuts back in again. So your system is running between 5 and 6.3 PSI which as mentioned is 99.9% chance MUCH more than you need.

Change the settings for a few weeks and see how it goes. And when your fuel bills start coming in, enjoy the savings!

================

I would like to recommend (HIGHLY!) that you purchase and read this book:

Heating Help

You will learn so much from this book that you will feel like an expert. And it's not all techie mumbo-jumbo... it's written with the homeowner in mind and is very easy to understand. Seriously, you will not be sorry!

================

Let's get back to the original problem ...

What is the status of this problem? Still doing the same thing?

There is a chance that lowering the pressure will help the situation, but as I mentioned, you may in fact have a defective 404.

 

I ordered a copy of the book. I've seen it recommended elsewhere as well.

I turned down the pressure settings to the .5 cut in, with the ~1.5 differential. Still hasn't fired up.

Is there anyway to manually fire the pa404? Or anything of the sort?

 

No, unfortunately there is no manual 'over-ride'.

To suggest that one could bypass an operating and safety control would be irresponsible of me. It would be unsafe to do so...

How well do you know how to use your multimeter?

Do you know how to measure continutity (ohms) ?

 

Is there a pressure gauge mounted next to the pressurtrol?

What does it read? The system has been off for quite some time, so I assume that it would be reading zero right now?

Have you ever noticed what the pressure is when the system is running?

 

Absolutely. I'm an mechanical engineer, so I'm a little out of my element when it comes to the electrical stuff, but know all the equipment fairly well.

 

OK then, with the power turned OFF to the boiler, and the pressure at ZERO, you should measure continuity across the two terminals in the 404.

Start with that...

 

But, you said that you measured 20.5 VAC at the gas valve, right?

So perhaps then the problem is with the valve itself?

20.5 IS a little on the low side, but I would think the valve would still operate...

I think you must know where the transformer is located? What VAC do you measure on the secondary of the transformer? Then, if you disconnect one of the wires from the transformer, what do you measure with no load on it, open circuit?

 

I wish I could find a manual for your boiler...

 

I confirmed continuity across the pressuretrol.

With the common lead from the multimeter on the relay case, I get 120V at the primary,and only 8.2V at the secondary, and to all the wires connected to the secondary. It's a little late, so I haven't disconnected anything and tested the voltage, but I'll try it in the morning.

 

Sorry, the transformer for the steam zone (not the one housed in the boiler boss relay) has a secondary of 20.3 volts. However, that's what the secondary is rated for.

 

So, I was able to get the cover that was frozen onto the gas valve housing off, and was greeted with a series of gears and springs. Voltage at the valve goes from 20-5 depending on whether the boiler is supposed to be generating heat or not, so I think all the controls are working right. I can manually turn the gears to get the thing to fire, and there is now a spring just sitting on the floor underneath the valve housing. I'm guessing it fell off of somewhere, but can't seem to figure out where it may belong. It's an old Honeywell valve needing only 20v, and I can't seem to find any info online about an old mechanical-type valve.

 

Oh my...

You need to stop what you're doing and have a pro come in and replace that gas valve.

Dangerous territory you are in now.