WH T&P valve drips on electric but not gas
We have a 6 gallon DSI gas & electric WH, new in 2014. On our first trip I noticed that when on electric, but not gas, the temperature & pressure relief valve would drip. So the dealership replaced ...
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IF t-stat is not tight against WH Tank wall it can cause overheating BUT if normal t-stat opens 'late' then it is still working unless High Temp t-stat opens. When Hi temp t-stat opens you will get a fault light and WH will not reheat until reset. So you would know if high temp t-stat opened.
Suburban WH use a 120V AC set of t-stats for electric and they use a 12V DC set of t-stats for propane.
Both sets of t-stats are pre-set snap discs----Normal is 130*F and High temp is 170*F. For BOTH electric & propane t-stats.
The T&P valve is set to open at 210*F and/or 150# pressure.
Atwood WH use one 12V DC set of t-stats for both electric & propane.
Normal set for 140*F and ECO (Hi Temp) set for 180*F.
T&P same as Suburban...210*F and 150#
Atwood has the XT WH that uses the mixing valve. Same t-stats for electric & propane but normal set for 160*F.......then mixing valve is set for 130*F output. Same Hi temp and T&P settings.
WEEPING of T&P is common when heating water in a closed system (such as RV plumbing system is) because water expands when it is heated.
A 'air pocket' by design is at top of WH Tank. It allows for the expansion of water when heated without the increase in pressure. (air can be compressed...water doesn't)
If air pocket is lost or marginal the increase in pressure is enough to cause T&P to weep.
Normal in a closed system. Not unheard of. Doesn't mean T&P is faulty.
You can re-establish air pocket
Turn water supply off
Open faucet hotside to relieve pressure
Open T&P via lever.......when water stops running out of T*P left it snap close
Close faucet
Turn on water supply
Weeping can occur with either Atwood or Suburban. Both reference issue in their manuals.
Air Pocket is by design
Suburban WH use a 120V AC set of t-stats for electric and they use a 12V DC set of t-stats for propane.
Both sets of t-stats are pre-set snap discs----Normal is 130*F and High temp is 170*F. For BOTH electric & propane t-stats.
The T&P valve is set to open at 210*F and/or 150# pressure.
Atwood WH use one 12V DC set of t-stats for both electric & propane.
Normal set for 140*F and ECO (Hi Temp) set for 180*F.
T&P same as Suburban...210*F and 150#
Atwood has the XT WH that uses the mixing valve. Same t-stats for electric & propane but normal set for 160*F.......then mixing valve is set for 130*F output. Same Hi temp and T&P settings.
WEEPING of T&P is common when heating water in a closed system (such as RV plumbing system is) because water expands when it is heated.
A 'air pocket' by design is at top of WH Tank. It allows for the expansion of water when heated without the increase in pressure. (air can be compressed...water doesn't)
If air pocket is lost or marginal the increase in pressure is enough to cause T&P to weep.
Normal in a closed system. Not unheard of. Doesn't mean T&P is faulty.
You can re-establish air pocket
Turn water supply off
Open faucet hotside to relieve pressure
Open T&P via lever.......when water stops running out of T*P left it snap close
Close faucet
Turn on water supply
Weeping can occur with either Atwood or Suburban. Both reference issue in their manuals.
Air Pocket is by design
