feed water to boiler

Bob D._2

Fellas, I have to (respectfully) disagree with some of the "common sense" reasons anyone would shut a M/U valve. By my lights - (1) Oxygen corrosion due to a slow leak is the least of your concerns. A leak is bad, you have to fix it. If you (the Owner) don't fix it, my "sympathy well" runs dry. (2) A means of make-up is required. While it may be true that it doesn't explicitly say anywhere that the valve has to be open, if the valve is shut there is no means of make-up. Anything else is semantic BS. (I'm not at the office, so I don't have all my references available to check.) Admittedly, make-up has to be properly piped and all, but Jezz-Louise, shutting the valve eliminates your first line of defense.(3) While it's nice to think that the (now) Code required LWCO will cover your tail if there is a leak, by the time this device trips you are probably already in the region where "bad things happen" (in most cases - my usual assumption) The BFP and PRV combo is the only way to go anymore - and there are a LOT of reasons. Not using this approach is indefensible. While my hands are pretty soft nowdays, I have done my share of real work, though usually on larger systems. I'd have to say, barring some really unique situation, that if I found a make-up valve shut, somebody would be out of a job. - Bob D., P.E., USN(Ret.)

Helgy_3

feed water to hot water boiler

Question for you wet heads. When a back flow preventer and pressure reducing valve are installed on a feed water line to a hot water boiler. Can the shut off to that line be left open during normal operation? If it can be left open are you not leaving yourself open to a world of problems such as the homeowner not knowing if his system has a leak or possibly oxyegen corrision. Let me know what you guys think.

Empire_2

In the past

I have left them open, but from reading a lot of good points from here, I now close after filling to desired fill pressure. This incorporated with a LWCO makes for a safer system.

Mike T.

CHARLES_4

WATER FEED/PRV

B&G instructs to close off the shut-off valve after filling w/their FB-38 et al.

Dave_4

vitodens high-limit == LWCO ?

Does one need a low water cut-off with the vitodens if the supply is shut after fill? I know that the boiler will fault if there is enough air in the heat exchanger to trigger the high-limit switch.

Helgy_3

failed boiler in part due to open feed water

I have herd it a couple of times. That somewhere in the system there is a leak, maybe not so noticable, but the boiler just rust out from oxygen corrosion due to the feed water being left open.

Ray Landry

I only do it when there is a lwco installed on the system. Otherwise, you're just playing russian roulette hoping that someone will notice when the boiler dry fires.

FredR

I installed my 1991 Burnham, h/w bb. The makeup valve has always been open. I just that it should be left n.o.!

[Deleted User]

My insurance carrier respectfully disagrees with you...

They have told us NOT to leave ANY solid makeup connections to the new systems we install, or they will DROP us from their rolls. We typically provide dual low water protection devices. One for an actual low water cutoff, and one for a low water pressure cut off.

In the 3 years that we have instituted this program on our new installs, we have had a minimum of call backs due to low water conditions, and in all cases, it was warranted.
Leak found and eliminated.

To provide extra water needed to compensate for the loss of fluid due to air elimination, we charge an expansion tank with high pressure water. Once the system has stablized for air elimination, the need for continuous access for make up water is nil, and if there is a leak in the system someplace (typical) it needs to be located and eliminated.

We had a worse case scenario about 4 years ago whereby one of the systems I had installed went into a leak situation on an occasional weekend home. It is simply amazing the amount of water damage that can occur from a small leak in a system pressurized to 12 PSI. Granted, it flowed for a week, but people DO go on vacations all the time. If we would have had to pay for it out of our pocket, it would have bankrupt the company. As it was, our insurance carrier told us that in order to continue insuring us the we need to do something DRASTIC to minimize their exposure to liability situations. When we proposed our "solution", they accpeted and continued to insure us for another year.

When it came time to renew, they dropped us (no reason given), and when the new company showed up and asked about previous claims, we told them what had transpired, and what we as a company were doing to limit their liability. THey said they'd LOVE to see it become an industry standard. It is now a standard on all new AHI installations.

Travel safe out there...

ME

John Ketterman

> (2) A means of make-up is required.


No, continuous makeup is not required. In a hot water system with no leaks, there is no way water can be lost. My system has been running for nearly a year with the makeup valve closed, and it hasn't lost pressure noticeably yet. It was opened last summer only because I drained the system for valve replacement.

The valve is left open by contractors for the same reason that reset curves are set too high...to avoid callbacks. It's not for the customer's benefit.

I do realize that not everyone has a perfectly leak-free system, but in that case, the leak should be fixed. This does not mean the leak has to be found. There are leak-sealer additives on the market that harden as they leak out; they work best on the tiny leaks that are so hard to find.

Jerry Boulanger_2

There is an alternative -

a packaged system feeder.

Lurker_2

Question To Mark A.

Which low pressure cut off switch do you use and who is the distrubitor?
Thanks For Your Help,
Mike

[Deleted User]

Bob D.

I sat bolt upright in bed this morning and thought to myself, "This guy was in the U.S.N. He's used to dealing with steam boilers. Of COURSE no one in their right mind would leave the automatic make up to their systems off".. Except me. Even with steam, I don't leave the autofill on. Washed out many a carpeted floor from auto fill hang up. It can mask a problem as well. I want to make a bumper sticker that says "Have you hugged your boiler today?"

I believe the homeowner SHOULD be responsible for the make up of water in their heating system, and obviously, they agree. I understand your point of view, however.

ME

[Deleted User]

Supply source: WW Graingers...

Square D pressure switch. Not sure of the part number, but it breaks at like 5 psi and makes at 10. Dual pole, single throw, normally open. 1/4" NPT taps.

We wire ALL incoming power (ampacity critical) to drop power should we see a low water or low pressure condition. I don't want ANYTHING (pumps) running during a low water condition.

ME