Prestige Solo 175 boiler not making temp with all zones on.
Found this website and looking for help with my Prestige 175 boiler. I recently moved into that house that had an older forced air oil burner and several propane wall units. The house is about 4200 sqft. I met a TT representative at a grand opening and he did a quick heat load and recommended the 175. I've learned this is not the best way to approach this but it is what it is. The house is very unusual with odd shaped rooms with tall ceilings, part of the living room is two stories with an overlook from the bedroom. I'm not sure this would fit the standard heat loss programs. The first year I installed the boiler, an indirect hot water heater, a radiant loop in the kitchen floor and one air handler to replace all the propane wall units. It worked fine all last season. This season I replaced the oil burner with another air handler. It seemed everything was working reasonably well and then something happened. Now when all three heating loops are on the boiler will not maintain the 140 temperature. It hovers around the 130's. When I force the boiler into the full fire mode it does come up sometimes but very slowly. I really think that it was maintaining temp until the beginning of December. My delta T's were are always around 15 to 20. I know the radiant loop is too small and may have to address this someday but I though I'd deal with the temp problem first. When I force it into the full fire mode the temp comes up very slowly but still no where near where I think the temperature should be. If I wanted a higher temperature it would never get there. In the year and a half it has never thrown a single error code. First I thought that it wasn't getting enough propane. But I can put five burners on the stove at full fire and one very low and do not see the flame height change when I turn on and off the gas to the boiler. The gas comes in on a 3/4 line with less than 1 foot from the regulator to a tee and then less than 4 or 5 feet from the tee to both the stove and boiler. Could something have happened to the controller?? It is definitely not a hard failure and does work but it does not seem to modulate. Flue temp is usually close but a little higher than the return water. The flue temp never gets more than 4 or 5 degrees above the boiler supply temp. It is set up P/S with only a Taco 007 boiler loop circulator. At the time this seemed like it would give me the 8 gpm required. There are two First Co FWA50-HW air hanlders with 1-1/4" piping and two Taco 008 circulators. I'm an electrical engineer and usually do everything around the house my self. But this hydronic heating is becoming a challenge. If the boiler was going over temp I'd think the main loop didn't have enough flow. But this is not the case. I guess a manometer would be nice but I don't have one... Any ideas on things to check???