About makup water supply.

Jean-David Beyer

I know it is controversial whether the makeup water supply should be left on on a hot water boiler. John Siegenthaler seem to believe it should be turned off once the air is out of the system. Others say it should be left on. I am trying to decide which to do.



If I leave it on, and there is a slow leak, I will never know until the oxygen and minerals accumulate and destroy the boiler. Or a pipe may break when I am not home and flood the walls.



If I turn it off, I may, but just may, have a problem dry firing. Probably not, since I have a low water detector that will cut off all power to the system if the water gets low. Furthermore, the boiler will detect the temperature rising too fast and shut down.



I turned it off and watched the pressure gauge and saw nothing even after a few days, so if it is leaking now, it must be very slow.



I have heard some people put water meters in their systems to monitor this. I found one on the Internet that might do the job:



<a href="http://www.jerman.com/dljmeter.html">http://www.jerman.com/dljmeter.html</a>



Is this what they have in mind? Do any contractors put them in systems? Would they use one in their own home? Does it make sense to put one in?

CMadatMe

My 2 cents

Is to leave the feed vlv on. I'm not familiar with John's article or quote so I don't know what context it what said in. I do know that in the 20 plus yrs I've been in the biz  I have never known or seen one shut off.

Could you tell me what article or book that John wrote that stated this. I'd love to read it.



Best Regards,

KevinCorr

temporarily off to test

You don't need a meter.

To check that you have no leaks, just shut it off for a while and keep an eye on the pressure. You can check for a day or what ever time you want to test, then turn it back on.

DanHolohan

I think

it should be off, and I agree with John.  The boiler should have a low-water cutoff. A feed valve can't protect against a low-water condition, and you're right, it will mask a leak and bring in lots of fresh water, along with mineral deposits

MIke_Jonas

Lots of different answers

There will be as many opinions on this as there are people on here.If you have a lwco, I'd turn it off.I was at a new customer last week, drywall guy had removed some insulation while doing some work. Left a "chimney" between the studs for cold are to blow from the crawl space up through to the attic, right across where one small zone was piped. Froze the pipe, burst, feed valve left open.$12,000.00 damage.

CMadatMe

Do You Know

what article or where John's thought on this are. I'd like to give it a read.

KevinCorr

antifreeze

Why the H..ll was there no antifreeze?

KevinCorr

Example of off

They had a small leak unnoticed from an air vent in the boiler room. It ran very slowly down the hot pipe and dried up so there was never water on the floor. After months the pressure got low enough that while the boiler worked fine, the upstairs zones did not circulate. Then it dropped to seriously below zero temps and it cost a service call to simply turn the water back on.



So now it is left on and with antifreeze, what is the down side?



Often we set up a glycol barrel with a shallow well pump instead as make up instead of using the house domestic water.

Jean-David Beyer

Reference to J.S.'s point about makeup water.

John S. wrote that in section 13.7 -- Make-Up Water Systems -- of his book,

 "Modern Hydronic Heating...", 2nd Edition, on page 490.



He says, "Unfortunately, a standard make-up water assembly can also be a

liability. Since it reacts to a decrease in system pressure, it will continuously

feed water if a leak develops in the system. If a situation where occupants

are not present, or are not aware of the leak, considerable water damage

to the building can occur. ...



"The hydronics industry continues to debate the merits of having an

automatic make-up water assembly 'active,' versus turning it off until

system pressure needs a boost. ... The author's opinion is that an

automatic make-up water assembly should be turned off once all portions

of the system have been in operation for about 2 weeks. This allows

sufficient time for the removal of the dissolved air initially in the

system. ..."

Jean-David Beyer

code around here would not allow that chimney effect

I am pretty sure that the code around here would not allow that chimney effect because fire stops are required at the bottom and, IIRC, every story thereafter. These days they require insulation in the exterior walls around here. The inspector specifically wanted a contractor who removed some of my interior plaster to leave that wall open so he could see if the insulation was replaced.

Jean-David Beyer

what is the down side?

The down side is if the leak is severe, you fill up the wall with water and this dry cleans the homeowner's wallet.



But you continue with "Often we set up a glycol barrel with a shallow well pump instead as make up instead of using the house domestic water." That seems to me to be a good idea. Because you can probably tell when the barrel solution level goes down and investigate before the unlimited supply from the water company can fill up the wall.



John S. suggests something of the kind: an automatic fluid feeder that consists of a small tank and a small metering pump that supplies water from the tank if the boiler pressure gets too low. You can put water, glycol-water mix, or whatever in the tank. He shows a picture of one like this: http://axiomind.sasktelwebhosting.com/mf200.php

KevinCorr

Good idea

That Pressure pal looks like a good idea. Using a shallow well pump and small barrel works but is expensive. See in the right corner next to the boiler.

hot_rod

new systems can "burp"

for days after start up. As the fluid warms and all the various zones kick on and off, expect some small air to vent.



With mod con boilers, most have pressure switches. if the system pressure drops below @ 10 psi they will lock out.



I'd leave the fill on for at least a week in heating season. Or a temporery Axiom or equal fill if you are worried about flooding.



I've missed crimps on more than one occasion. They seem to pop off when hot fluid hits them, so flooding is a concern in a "first time on" system.



That is where the fill systems with tanks and alarms could be handy, even for a start up device. It would show exactly how much the system took on, also.



hr

Jean-David Beyer

With mod con boilers, most have pressure switches.

My W-M Ultra-3 does not seem to have any pressure switches. They do require the boiler to be piped primary-secondary. And they have temperature monitors so if the temperature of the heat exchanger goes up too fast, it cuts off. Too fast implies low water, it seems to me. Similarly, if the output temperature exceeds the return temperature by a lot (58F ?), it assumes something is wrong (no flow in secondary comes to mind) and cuts off too.



J.S. did suggest running the system during the heating system for about 2 weeks before turning off the makeup water. I have had my makeup off for about a week now, and I see no pressure drop. So I have either no leaks, or my expansion tank is compensating for them.



When I actually start heating, I will have to turn on the makeup for two weeks, because the secondary circuit is not running (too hot inside and outside), so those circuits have not been fully deaireated yet.

Tim_41

water feed

I have had a few freeze ups on oil fired boilers.  Most  were on the first or 2nd floor.  Once the pipe burst: the floods begin.  New floors etc.  I think shutting the feed off is fine, but after a bit of time once the air is purged.  Having a LWCO near the boiler did not help.  Maybe a PSI system like the mod/cons have would be the best for the oil fired boilers. 

KevinCorr

anti freeze

No real reason for frozen pipes since they invented glycol.

Tim_41

glycol

No question about the antifreeze.  But, it is another often overlooked item that needs to be checked during each cleaning.  I won't put antifreeze in unless the customer really wants it.  Unfortunately the freeze up I was referring to was due to the fact that the renters turned the heat off in January and used electric heaters to "save fuel". 

Jean-David Beyer

Extra LWCO.

I would not expect an LWCO in its usual place to protect against water running out from upper floors of an hydronic heating system. But one could buy an extra LWCO device and install it at the top of the system. Instead of having it stop the boiler, you could have it set an alarm.



I would not do this myself (too expensive), since I look at the pressure gauge every day (at least, my homeowner's manual says I should) and would see the trouble soon enough. For me, looking at the pressure gauge daily is easy, since it is right next to my car in the garage, so I can see it every day I drive.

Jean-David Beyer

Another reason to turn makeup off.

In addition to John Siegenthalers recommendation, Dan Holohan supplies an even more dramatic reason to install Low Water Cutoffs and turning the makeup water supply off. In the referenced year of P&M, starting on page 8.



http://www.heatinghelp.com/article/183/Plumbing-Mechanical-articles/776/1996



I have an LWCO and I will be checking the system pressure regularly on my system.