Raypak 062234B Unitherm Governor, Metal Headers, 206A-407A ASME, RP2100 R185A/B-R405A/B, Versa 185A/B-405A/B Pool Heaters

The Unitherm Governor (U.G.) is Raypak's thermostatic mixing valve. It sits in the inlet/outlet header and holds the water inside the heat exchanger between about 105 and 115 degrees F, warm enough to keep condensation off the burners and cool enough to slow scale in the tubes. This is the version for heaters with metal headers; polymer-header heaters use Raypak 006719F.

Older models:

• 206A, 266A, 336A and 406A ASME heaters with cast iron headers, the header Raypak used before December 2019
• RP2100 R185A to R405A (1998 to 2004) and R185B to R405B (2003 to 2004) with the ASME cast iron header
• Versa 185A, 265A, 335A and 405A (1986 to 1988) and Versa 185B, 265B, 335B and 405B (1988 to 1993)
• Versa 105B with brass headers (1999 to 2006)

Not for polymer (Capron) header heaters, which use 006719F, or for the Versa 055A and 055B and Spa-Pak 053A and 053B, which use governor 600885.

Related parts on the same headers: U.G. retainer spring 013792F and U.G. plug 013738F.

Good to know: On ASME heaters with bronze headers, built from December 2019, Raypak's manual says the governor and bypass valve are not replaced separately. Those heaters take the complete U.G./Bypass Assembly: 018759F for the 206A, 207A, 266A and 267A, and 018758F for the 336A, 337A, 406A and 407A.

Raypak's repair guide tests a governor by placing it in hot water (105 degrees F or hotter, 130 degrees F or hotter for the ASME version) and watching for it to open as it warms. Do not heat it with an open flame. When a tube bundle has failed, Raypak recommends replacing the Unitherm Governor and inspecting the bypass, because the same water conditions have very likely damaged them too.