Water supply to boiler

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Old 04-09-19, 02:10 PM
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Water supply to boiler

I have a triangle tube prestige boiler and am wondering if the ball valve that supplies water to the boiler should be left open. I just had the system bled of air by the service man and he left this open. Not sure if it was before or not. Here is the flow of the water entering the boiler loop:
The water supply pipe has a ball valve, followed by backflow preventer, followed by a watts pressure regulator followed by another ball valve, before the water enters the heating loop. Currently both are open. Should these both be open?

Thanks for the help.
 
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Old 04-09-19, 04:15 PM
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Normally the water fill service valve(s) is(are) left on. The pressure reducing valve is supposed to keep the pressure near 14psi. If you see the pressure rising...... there's a good chance your reducing valve is not working properly.
 
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Old 04-09-19, 04:54 PM
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The preferred position of that isolation valve has been debated until the cows come home. If you can assess the risks either way, then take your pick.
 
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Old 04-09-19, 05:54 PM
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You're right Gil..... d*amned if you do and d*amned if you don't.
Turn it off and possibly run low on water.
Leave it on and have the system overfill and piss out of the relief valve.
 
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Old 04-10-19, 07:29 AM
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Other points in this endless debate:

One rationale to keep fill valve open on hydronics systems is to prevent explosion if water level in boiler fell making it a steam system.

Out-door-reset adds another issue where hydronic boiler temp rises and falls over season from 140F to 180F. With ODR I find with fill valve kept open, pressure creeps up over season.

With ODR, when pressure regulator adds water at 140F to maintain 12 psi, then at 180F pressure goes up. Over a number of these boiler/ODR temperature cycles, pressure increments up.

In very cold weather when the days's outdoor can range from 0F to +30F I close fill valve.
 

Last edited by doughess; 04-10-19 at 07:49 AM.
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Old 04-10-19, 05:10 PM
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I'm surprised to hear that ODR leads to seasonal pressure increase. My hot-water boiler is warm start, and is completely shut down during summer months. I've observed no seasonal or other pressure creep, even with the water feed valve either shut or open.
 
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Old 04-11-19, 03:13 AM
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With every device on the boiler working properly there is no pressure increase above the normal operating parameters.at any time during the firing of the boiler and the heating of the house as long as the complete heating system does not leak or expel any water. The feed valve open or closed makes no difference as long as every device is working properly. Working all over Pennsylvania and parts of Ohio and West Virginia code's usually, but not always, required that the feed valve remained open 24/7 to maintain water feed to the boiler in case of a discharge of water by any means. Contrary to this, if the heating system was filled with an antifreeze solution, there had to be a place for an actual break in the feed system piping where a piece of the piping was removed to insure that the potable water system could never be contaminated by the antifreeze. I have been retired for 10+ years but I would assume that that that code would never be relaxed. my 2 cents
 
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Old 04-11-19, 07:58 PM
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There are several possible reasons why my system pressure tends to increment. It is high mass with 30 gallons of water and 7.4 gallon diaphragm expansion tank, 13 heating elements are fed from 280 feet of 1” copper lines with monoflow/diverter tee's.

Elements located 18” above main are connected to the tee's with 1/2” copper. Multi tube elements are natural air traps so each has Watts auto vent.

Do not buy that in a sealed system there is no pressure variation when water temp varies from 140F to 180F. Yes, expansion tank should minimize it. System has a 5" 30 psi gauge that rises a little on very cold days. Over the season that can add up.

The 60 year old system works well, is very efficient so I live with minor idiosyncrasies.
 

Last edited by doughess; 04-11-19 at 08:31 PM.
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