Hi all- So last week we had an issue with our heater that I thought we resolved but it happened again today when I went out to turn on the heater. Below is what happened, how we thought we resolved it and what happened since. Any advice is appreciated! Regards, Peter Last Week Issue - last...
You seem to have excessive restriction, but nothing obvious is being found.
You can remove the manifold and verify the internal bypass if you want. That would give you the opportunity to look at the ends of the heat exchanger. Based on the condition of the thermal regulator, it's highly likely that the heat exchanger is compromised. The heat exchanger is likely severely corroded or maybe scaled. You would need to replace the manifold O-rings if you remove the manifold.
You should be able to reach into the inlet with something to depress the spring part and watch the disc part while looking in the hole where the thermal regulator goes. See picture of internal bypass.
Other than the 7 suggestions I made earlier. I don't know what else you can do.
Maybe install a 5 psi check valve external bypass for the heater in addition to the 7 suggestions.
Ok, thanks for all the help! Really appreciate it. One last question - is there a specific spring I need to get, or is that a generic item? The part diagram doesn’t list a part number.
In case it matters, the heater was mfg in 2012. I am very hesitant to remove the manifold since the heater currently functions. I fear if I remove the manifold and do need a need heat exchanger, I will accelerate the need to replace the heater.
You can unscrew the tab feeder and look in the hole to see if anything is caught on the venturi tube.
There's a set screw at the base of the feeder that you need to remove before unscrewing the feeder. Look in the hole at the base for the screw. If the internal bypass plunger broke loose, it would likely get caught on the venturi tube in the feeder T base.
Thanks James. Checked those as well and all looks clear. I am thinking this is just inaccurate reporting by the pump.
I just played around with the heater a bit and have a few more data points. The exhaust temperature at 1700 rpms is around 312. The exhaust temp at 1900 rpms is around 308.
I ran it for 10 mins at 1900rpms and then 10 more mins at 1700 rpms and got no low flow error. Is that long enough for it to throw a low flow error? Does the heater throw an error any time it has less than 40gpm of flow?