have a tempering valve installed for the domestic hot water and make sure there is not more gallons per minute flowing through the tankless water heater coil than what is required. I,ve seen situations where more water was flowing through those coils than what the heat transfer capability could keep up with. Also follow the other recommendations listed in the previous posts.
Yes, thats what the silver thing is, an air vent of some kind.. You know what would be neat, a little brass whistle. But I digress.
Yes, the temp seems to be all over the place on the high limit. So far as I can tell with my defective guage at least. My lowering of the pressure slightly to 12 pounds static seemed to work out ok last night and as the temperature came up it hovered between 14 and 16. This morning it was at about 15.5. I imagine a tankless coil leak would bump it up a lot.
But I still have this big bang. I dont hear any gurling or running water just a big bang. I am still in the process of locating the source of the big bang. I thought I had it isolated to one zone at least but I found that one of the zones was left open by the heatco. So now I have it narrowed down to two zones. It could simply be an expanding pipe thats become dislodged from whatever piece of construction debris it once rested apon.
I appreciate, and will heed all of the advice I have received from you guys. It worked out really well for me on my last heating system and I managed to tune it just about perfectly.
FYI: For boilers that overshoot their aquastat settings by a large margin, take the aquastat control off the well and be absolutely sure the sensing bulb is fully installed in the well. I've found many a sensing bulb no where near fully installed and that will make the boiler overheat and make for sluggish response. Also, make sure the differential setting is correct for the application. When there's a tankless heater in use, WITHOUT a temp valve, diff should be tight, like 10°....but if the boiler DOES have a temp valve with a tankless, the diff can be looser. Boilers with indirect HW tanks should have a real loose diff setting (25°) since the boiler runs off the high limit to heat the tank and the low limit with a loose diff will allow for longer runs times on the circ.
Allright, Today Is the day. They are coming to clean and inspect the system. Sometime between 12 & 4..
So far for sure we need a new guage and possibly the aquastat is bad or misconfigured.
I have located my HAMMER issue. Its the freaking zone valve shutting off. It never did it until it was replaced. I understand replacing it with a Taco or a B & G will allow it to close slowly and reduce the hammer. Or replace them with circulators, or install a pressure reguilator bypass.
Ill bring that up when they come. I know I will be greeted with a blank stare.. After this Im calling plumbers cause my heatco seems to just want to sell complete systems.