Bad mixing valve?

Larry Weingarten

Hi @frankjc , A few thoughts about different things: To "feel" what the tempering valve is doing, run hot water someplace and then feel the three pipes connecting to the valve. If the "cold" line goes from room temp to cold, you know the valve is mixing in cold water. If the "hot" inlet isn't all that hot, you know there is a problem with hot water supply. The outlet temp will depend on what he others are doing, but it's a good way to confirm flow.

Pulling out the guts will give you only what's coming from the boiler, which could be variable and dicey.

About going electric, you might want to consider using a heat pump water heater. There are rebates for them and they can compete with fuel fired units because they can have a good coefficient of performance (COP).

Yours, Larry

frankjc

Tried it with the guts taken out of the tempering valve, no difference. To me that means no hot water getting to the valve. 
Probably a clogged coil.
Considering an electric water heater. I have lived here 12 years and have never had good hot water.
If I go electric, how to I tell this boiler not to fire up to make hot water?

Intplm.

frankjc said:

Knob is turned all the way hot. Always has been. I'm done playing with it for today. I was thinking about taking the thermostat completely out of the valve to see what happens. I'm really tempted to just get an electric on demand hot water heater. My hot water has never been much good anyways.

Not that complicated changing the the tempering valve to a mixing valve. Set your mind to it. You can get it done, and maybe your its your best bet at this point.

frankjc

Inside the boiler, is the hot water coil submerged in water, or heated by a flame?
If the boiler was low on water would it cause this?

mattmia2

The coil should be submerged. That wouldn't affect flow, just heat transfer. It could be clogged with minerals from the water on the domestic water side.

Is the boiler set up for steam or hot water on the heating side?

frankjc

Hot water.
My friend was wondering if low water level would cause t

hot_rod

On problem with some thermostatic mixers is when the coils lime up you get a big pressure drop. If the cold pressure is higher than the hot, the valve will not mix properly, or at all. Most want less than a 2:1 ratio cold to hot.
Be nice if you could flow test the coil somehow, disconnect the hot and run water thru it, see how it flows..

hot_rod

Here is the troubleshooting procedure, they do not mention a pressure ratio. They indicate 2 gpm min