MikeG88
Member
I have a Navien CH210ASME-LP that was installed just over a year ago (my builder swapped it out on their dime for a CH210(non ASME) that had the 2 second burn time problem that he couldn't solve- verified gas pressure multiple times, swapped air pressure sensor, changed burner rods etc, but they never tried to adjust the gas mixture screws). My current concerns with this unit is that sometime when thermostat calls for heat the unit ramps up for a short period but at the point where it would normally "shift gears" the green burner light on the control pad occasionally goes out and comes back on (usually an instant or so later)Seems to do this more often if DHW was recently used. The other time it does this is when it gets up to the set point temperature- the burner light may go out- it comes back on after a varying time (or ofter the T-stat will be satisfied shortly after the flame shuts off therefore no need to restart). I've been told that the later may have to do with the unit not being able to "turn down" as fast as it wants when it hits the target, so it restarts the flame and may allow a short time in between. I'm wondering if this is true and may also be the reason that it sometimes does it near the beginning. (It doesn't sit there and do it repeatedly like the 2 second burn time problem I previously had with the old unit- as well as others on this forum- so I am naturally concerned)
I am running the unit at 60% capacity, with a Taco pump set to slow- that speed was recommended I believe because return was coming back too fast- it's a single zone and house is only 24 x 48. The exhaust is plumbed for the higher temp and the board is set for that. I am running it with a Honeywell heat only thermostat set to 3 cycles per hour. I do NOT have the outdoor reset. I have tried different supply temperatures from 180 down to 150.
I am in Middlesex county, Connecticut. The house is a single level ranch (modular construction) on a full basement (walk on on one end). It has 1152 sf of area. It's not even four years old yet, obviously 2x6 walls R20 and R49 in the ceiling. If I add up all the BTU requirements on the Heat Loss Calculation page of the plans I get 28,196 BTU. But is says that its 90 deg. Design Temp. Diff. (and) Design based on 180 deg water temp at 3 GPM. If I am interpreting that correctly- it would mean that at 70 deg inside it would only need that much BTU when it is 20 below outside (70 inside - 90 differential = 20 below)? Being a modular they may use 20 below as a design temp because house could be "set" anywhere. The calculation page calls for 51LF of baseboard - there is actually 54LF installed (and I keep the louvers open on all of them).
I asked the builder if this unit was over-sized for this house and I was told the size is really based on the DHW that could be potentially called for (2 bath rooms, washer, dishwasher etc). I haven't noticed the burner cycle off and back on when using DHW - I've opened multiple faucets and checked -but burner light always appears to be on.
I am running the unit at 60% capacity, with a Taco pump set to slow- that speed was recommended I believe because return was coming back too fast- it's a single zone and house is only 24 x 48. The exhaust is plumbed for the higher temp and the board is set for that. I am running it with a Honeywell heat only thermostat set to 3 cycles per hour. I do NOT have the outdoor reset. I have tried different supply temperatures from 180 down to 150.
I am in Middlesex county, Connecticut. The house is a single level ranch (modular construction) on a full basement (walk on on one end). It has 1152 sf of area. It's not even four years old yet, obviously 2x6 walls R20 and R49 in the ceiling. If I add up all the BTU requirements on the Heat Loss Calculation page of the plans I get 28,196 BTU. But is says that its 90 deg. Design Temp. Diff. (and) Design based on 180 deg water temp at 3 GPM. If I am interpreting that correctly- it would mean that at 70 deg inside it would only need that much BTU when it is 20 below outside (70 inside - 90 differential = 20 below)? Being a modular they may use 20 below as a design temp because house could be "set" anywhere. The calculation page calls for 51LF of baseboard - there is actually 54LF installed (and I keep the louvers open on all of them).
I asked the builder if this unit was over-sized for this house and I was told the size is really based on the DHW that could be potentially called for (2 bath rooms, washer, dishwasher etc). I haven't noticed the burner cycle off and back on when using DHW - I've opened multiple faucets and checked -but burner light always appears to be on.
Last edited: