Indirect water heater

Dana

You don't.

chuck shaw

Heat exchange

When a cold start boiler gets a call from the indirect for heat, how do you keep the heat from going from the indirect back to the boiler, and therefore running out of hot water? I was helping a friend of mine today, and I asked him what he planed on doing. He didnt have an answer. He understood what I was saying, but didnt know how to stop it from happening.

Normally I install a Buderus, with the Logomatic control, or a Munchkin, so I have not run into this issue.

Any ideas would be helpful.

Thanks in advance,


Chuck

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chuck shaw

timers/delays

there isnt a timer or a delay, that would allow the boiler to run for a couple of minutes before starting the circulator feeding the indirect?

Chuck

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Big Ed

Reverse Aquastat

You can hook up a reverse aquastat "B" to prevent the problem .I believe the 2107 has a setting to prevent the circulators from kicking on below a desired temperature for condensation .

Alan(CaliforniaRadiant)Forbes

Never really

thought about it, but you're right; the warm water coming back from the indirect would pre-heat the boiler.

The Viessmann Vitogas boilers have a thermostat that disables the pump until the boiler gets to 130° to prevent condensation. That feature could be used for more than one purpose.

But come to think of it, it really doesn't take very long to heat the boiler water; there's only a few gallons in the indirect system.

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Steve Eayrs

Chuck, Most cold start boiler I know of have their own recommended control statigy. Some supply and include whats needed, others just recommend something.
EK is a good example of a non-condensing oil fired colds start boiler, and their controls don't open the dhw zone, or any others unless the boiler return temp. is warm enough.

A triple aquastat (double acting aquastat) would work, as they canbe set up so the pump/zone doesn't kick on unless the temp. is above the low setting.

Or as other recommended a normally closed aquastat that opens on temp. rise would work. I'm sure you could also give the dhw priority this way too.

If this is a non-condensating type boiler, it gives you another reason for wanting to do this.

Steve

jerrygb46_4

reverse acting aquastat

Seem like everybody hooked up too all this HI-TECH boola-boola and forget about the OLD L4006B (B)as in boiler).Just set it at 130 deg and Walla.

Tom M.

Amtrol

Amtrol's latest version of the smart control (the one with three buttons instead of just one) has a prepurge setting. the options are 0, 4, and 8 minutes. I believe the manual says that it is useful for cold starts and for larger boilers.

Tom M.