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Posted by Heatpro on January 22, 2006 at 11:10:02:
In Reply to: a few minor problems after our repiping posted by Dave on January 22, 2006 at 08:57:18:
It is likely the expansion tank is small now, as glycol also increases expansion volume. At 180F, you shouldn't have more than 24 psig. The reset pressure of a 30 psig boiler relief valve is 25 psig, so the pressure should never exceed 25 psig for any time or it is more likely to weep.
A boiler should NEVER have a T&P valve, as the T part of it is temperature and you don't want to dump water just because the water is hot. You want a boiler pressure relief valve to work due to pressure in the boiler.
In a multi-pump system, you need a weighted check valve (flow control) on EVERY zone, including the phase 3, as any water from any other zone can pump backwards through that phase 3, increasing its temperature. The coil resistance in the phase 3 is high; but that simply means less flow goes through from the other zones, not NONE without the check or flow control.
I hope you have a tempering valve on the phase 3 outlet to protect guests.
If you can, lower the Ergomax control to 140F to see if the boiler won't condense and to save energy.
I'm off to Las Vegas til Feb 4, so keep warm. I'll look at the pictures when I return.