Re: '47 356 modern thermostat
Posted by HH56 On 2018/9/11 17:57:20
How much too small? I am fairly sure the THM 91 is what I have in mine. It fits and the ring keeps it in.
Here are the specs for the 91. The flange width compares to a new bellows style thermostat from Max that I have. Flange on the bellows is 2.452 and at 2.49 the pellet spec should have it being a bit larger than the bellows. I measured the opening in the housing to be 2.490 or just under 2 1/2" and the ledge the thermostat rests against has an opening of 2 1/4 so there is 1/8 all around for the flange to seat. Ring side should be slightly larger than that but I don't have a spare to check what it compresses down to.
The 91 should be a tight fit if anything. Any chance the wrong thermostat was put in the box or has your housing eroded or rusted away somewhere?
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Here are the specs for the 91. The flange width compares to a new bellows style thermostat from Max that I have. Flange on the bellows is 2.452 and at 2.49 the pellet spec should have it being a bit larger than the bellows. I measured the opening in the housing to be 2.490 or just under 2 1/2" and the ledge the thermostat rests against has an opening of 2 1/4 so there is 1/8 all around for the flange to seat. Ring side should be slightly larger than that but I don't have a spare to check what it compresses down to.
The 91 should be a tight fit if anything. Any chance the wrong thermostat was put in the box or has your housing eroded or rusted away somewhere?
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