On Jul 5, 7:07 pm, "Wally" wrote:
I just had a new propane indirect water heater (works off my boiler) installed 2 days ago. I am on a well pump. It has plenty of hot
water, but when taking a shower, every time the pressure tank kicks on, I get a blast of cool water for about 10 seconds, then the
pressure tanks turns off and it is hot again for about 2 minutes till the next cycle. The plumber told me it may be dirt in the
washer machine valves and to turn the water supply off to the washer and see if it cures the problem, but it still does it. I never
had this problem with the old water heater. Anyone have any other ideas?

Duh! Wally, when I read indirect water heater, I assumed it
was "tankless". You know the old saying about when you
assume things........... Your heater has a tank doesn't it?
In that case, pressure and rate of flow could the culprits
but in a different way. If there was is restriction to the flow
of water going into the tank, it might cause the problem.
Is there a expansion tank on your water heater? Dip tube
failures or the lack of one can cause also cold showers.
I wonder if your heater's T&P valve is opening up when
your pump comes on? Anyway I'm sure someone out there
has seen the your exact problem before.

[8~{} Uncle Monster