Boiler comes on inconsistantly

brucem

Old house and pressuretrol replaced with a used one last year.Also pressure dial replaced as well.

 Normally the system came on and went up to about 3.5 psi, then stopped and kicked in again at about .5 psi, which gave the system time to come down from 3.5 psi.

But when the system was reset it was coming on at 1 psi and only going to 2 psi, which gave fairly rapid on and off firing of the boiler.

 Now to me at leat it seems the longer the system isn't firing but the radiators are hot the faster the system heats the house up. So when the system fired and the pressure came up to 3.5 and shut off the radiators are hot and stayed hot until the boiler fired again.

 Now sometime the boiler comes on and stays on until 3.5 psi, but the cutin to fire the boiler is inconsistant, sometime going down to .5 other times coming back on at 2.5 or even 3. Last time the tech was out at my home the loop under the pressuretrol was clogged and this same thing hapened, but I'm not sure if this is the issue now or not.

 I like the pressure higher, but the techs set it lower. maybe that loop is clogged, is there a way to tell ?

Jamie Hall

You may like the pressure higher

but it isn't doing you any favours.  Residential steam systems -- and even some bigger buildings, such as the Empire State Building in New York -- do very nicely with a maximum pressure of 2 psi.  Many residential systems, in fact, work best with a maximum steam pressure of less than 1 psi (some won't work at all with more pressure than that).



The erratic behaviour of your pressuretrol suggests that either it or the pigtail is clogged (check not only the pigtail but also the opening to the pressuretrol itself) or that the pressuretrol isn't functioning properly.  They are pretty bulletproof, but they can fail, and erratic operation is one symptom of that.  You really don't want a failed pressuretrol, particularly if you only have the one, as it might not cut the boiler off on high pressure -- which would be interesting, to say the least.



You will probably happier -- and richer -- if you check that 'trol very thoroughly and, if you have any doubt about it,, replace it.  Then set it to cutout at about 1.5 to 2 psi, and cut back in at around 0.5 psi.  It will probably save fuel.  It will also probably reduce premature wear and tear and failure of things like vents and traps and valves...

brucem

Attempt repair myself

Just wondered how difficult it was to clean the pressuretrol myself. Obviously I don't want to do it with temps around 0, but this weekend it is supposed to get warmer.

 I did look inside the pressuretrol, and last time it was worked on the tech left the wires sticking above the housing, well those pressed down on the valves below and that itself caused problems. So just getting techs that know what there doing is getting harder and harder to find, especially in the area I"m in about 20 miles north of Boston.

 So should I attempt the repair myself ?

Jamie Hall

Should you attempt a repair yourself?

That's one of those questions.  I have no idea how handy you are, or familiar you are with controls.



Pressuretrols (and vapourstats, which are very similar) are rather delicate contraptions.  They are also safety devices.  On the other hand, they are pretty simple, in principle -- just a diaphragm, a spring or two, a couple of adjustable linkages and a microswitch.



Obviously the first step would be to find out why it isn't working properly, or better yet to verify -- with a low pressure pressure gauge -- that it isn't.  Then to diagnose.  Then to repair if necessary.



And, as I say, I have no idea how handy you are so I have no recommendation to make...

icesailor

Diaphragms:

A warped diaphragm can't be fixed and often can't be seen as the problem.

How much do you pay for house insurance and what is the deductible if something is damaged. How much is a pressuretrol?

I can and will fix ANYTHING!!

I learned years ago that some things aren't worth trying to fix and that a new one is far better. A used one is only temporary until I get a new one. Same with used gauges. I've seen them off right out of the box.

nicholas bonham-carter

DIY repairs

You can do it yourself if you have the right tools:

The most important would be a low-pressure 0-3 psi gauge, on a tee with the code required 0-30 psi gauge (useless for diagnostics!!!!).

As you remove the wires from the pressuretrol, label them as to where they go. Inspect the opening in the bottom for debris, and flush out that port and the pigtail, if necessary. After you have reinstalled the pressuretrol, the low-pressure gauge will show you if the cut out and cut in are functioning as needed.

If your boiler is short-cycling, as it begins to make steam, then check your main (not rad) vents, on the dry returns. When these are non-functional, or undersized, they are the fuel companies friend as they require extra fuel to force the air out of the system.--NBC

brucem

Repairs

Sounds doable, I think my main problem is forgetting to flush the system every month. I was told to do it while the system is fired in order to use the steam to get rid of any sediments.

brucem

Couple of Pics and more fun

Heres a couple of images, pus this morning for some reason, heat didn't come on at all. Its done this at least a few times each winter. Usually I just cycle the burner on/off switch and it come right on. Theres also some aluminum wiring on the safety shutoof over the boiler and I'm wondering if that has something to do with it.

nicholas bonham-carter

Something sticky

Something in the chain of safety devices must be preventing the burner from firing up. Next time happens be ready with a piece of wire, to jump out electrically all the safeties one by one to see which one is preventing ignition. If this is electronic ignition, then suspect that system also, or a thermocouple on a standing pilot.

Why was your used pressuretrol replaced?

You want the boiler to fire reliably in this weather, to avoid frozen pipes.--NBC

brucem

Its a thermocouple

Which is great when the power goes out, I'm really surprised they don't all have these by now.

But I think, and I'm guessing here, that withthe minimal voltages by the thermocouple, any extra resistance would be a killer for this system, such as maybe poor aluminum wiring, corrosion(I'm only about 500 yards from the ocean), and poor wire contact at connections.

 

Jamie Hall

Thermocouples

are all very fine, but not only do they not produce much voltage, they don't produce much current either -- and it takes very little resistance to defeat them.



Aluminium wiring?  Ah... no.



I must admit that my reaction, looking at the pictures you posted, would be a nice new pressuretrol and then set about rewiring the whole control system in copper, carefully and neatly.  You might not find the problem -- but you might eliminate it, too, in the process.



NBC's suggestion of jumpering out each safety in turn is not a bad idea, either -- but don't leave them out of the circuit.