Lowering pressure

steve_173

I've got a 0.5-9psi additive pressuretrol on a new boiler in an old home. As it's gotten colder, the system tends to need more feedwater. There's one clear leak I need to fix, but it also tends to puff steam from some vents.



It's hard to read the pressuretrol accurately. The cut in was a bit above 0.5 psi. Is the additive set to 1 as I see the 1 facing the front of the pressuretrol? I don't see an arrow indicating where the setting position is located.



How do I go about lowering the pressures which I suspect might not be helping some of these leaks. What is the technique to tweak the cut in and additive values?



How much feedwater is considered ok? This is an Intrepid 50.

Hap_Hazzard

Pressuretrol & makeup water

Yes, the "1" should be facing you when the differential is set at 1 psi. The "pointer" should be a vertical black line on the switch directly above the thumbwheel, so the number facing you should line up with it. You can also tell it's set to the minimum value when it's turned all the way to the right.



If the pressure is exceeding 1.5 psi, the most likely cause is a clogged pigtail. If you remove the pressuretrol you should be able to blow air through the pigtail. If you can't, you need to replace it.



Normally a steam system should not lose water, so the less you lose the better. If you're losing condensate, that's basically distilled water. All the minerals in the tap water you add to the boiler remain behind when the steam goes out to the radiators. If any of the steam fails to return as condensate, the concentration of solutes in the boiler water increases, and when you add more water, it comes with solutes of its own, so the concentration gets higher and higher until they reach saturation and precipitate out, forming mineral scale. This scale impedes heat transfer, making the boiler less efficient and putting stress on the cast iron because it runs hotter, and eventually leaks develop between the sections.



Constantly adding make-up water wastes fuel and shortens the life of your boiler. Get after those leaks with a vengeance.

ChrisJ

makeup water

I slightly disagree with hap on makeup water in regards to never loosing any water.  As far as I can tell any system with vents must loose some amount, otherwise the vents would never close.



My system looses some, though very little.  I just added a small amount tonight when the burners first fired up during a cycle.  This way the fresh water is boiled immediately to prevent corrosion issues due to dissolved gases.



For minerals I beleive my water treatment takes care of that as long as I maintain the proper level of treatment.  I will be doing a pretty thorough blowdown and cleaning in the spring as well and of course re-adding the water treatment.



That said,  the less water you add the better.  I don't know exactly how much my system has lost over the past week as its been pretty cold here, but I can tell you on mild months I can do 2 or 3 months without adding water.  Make sure you have no leaks at fittings or pipes, tighten up all valve stem packing nuts, make sure your vents operate correctly and you should be in business.



I only manually add water and I only do it at the very beggining of a heating cycle so I'm sure that fresh water gets boiled immediately.

steve_173

Rectorseal Steamaster Tablets

Do you mean these: http://www.rectorseal.com/product-data/steamaster-tablets/dssteamaster.pdf Where these hard to find?



Where do you drop them in? Is there any downside? I don't think my new boiler had any treatment at all. This is it's first heating season.

steve_173

steve

How do I set the pressuretrol to its lowest setting? It hits 0.5psi, then the screw can still turn to be looser? I only have a 0-30psi gauge so who knows what pressures are running. The vents don't spew water, but do vent some steam. I'll hopefully get the known leak soon. Then watch to see how much water is being added.



System seems to run a bit better with whatever amount of pressure reduction I did. It couldn't have been more than 0.5 psi. The only downside I see is that one radiator at the end of the line doesn't get fully heated. I think that's because the boiler is sized properly and the mains are not yet reinsulated.

ChrisJ

steamaster

Hi Steve,



A lot of info can be found on this thread : http://www.heatinghelp.com/forum-thread/143361/Steamaster-tablets-water-treatment



I bought mine from Amazon, but they have not had them for a while.  I put mine in via the skim port.  Only 2 is plenty of treatment, 1 is enough for many but don't ever follow the instructions on the bottle and use 12 or whatever insane amount they call for.

steve_173

How else can these tablets be put int?

I can't get it in my skim port because that is used as the take off for the indirect. There's a large tapping with plug on the boiler above the skim port.

ChrisJ

Any which way you can

Any way you can get them into the boiler is fine.  If you can remove that plug it'll work.

Boiler Talk

The poorly fitted Pressuretrol

OK.  I think the pressuretrol isn't made with precision.  Others will say that's an understatement.  I got a new boiler in September 2011.  Well, I have a P-trol with a cut-in shown on the outside.  I think we are talking about the same model.  404A  I could not obtain a maximum pressure below 3 lb.  Everything was set to the scale and dial.  That being the case I found the internal switch mounted very high.  Loosening the HEX screws allowed me to push the switch down and obtain a much lower maximum pressure.  In fact, I claim I have a pressure below 1 lb!  I obtained a lower cut-in, but that involved bending the thingy upward that sticks outside the scale.  Mine was actually pointed downwardly, not at a right angle, so I never could achieve .5 lb.  I have a 5 lb gauge and see a cut-in just above zero.  I kid you not.  Give me that much.  Did I do wrong?  You could try tweaking or at least investigating.  If you do anything, cut the power first!