Forum Discussion

Kountryguy's avatar
Kountryguy
Explorer
Oct 31, 2020

Water Heater Temp

I have a Suburban 12 gal. dsi water heater. Today it does not seem to be heating the water as hot as previously. Both the electric and gas heat it to about 108 degrees. Is it possible that the thermostat is bad? Any suggestions? Thanks.
  • Kountryguy wrote:
    Old-Biscuit, Are you able to provide any more info on the dip tubes you mentioned? I looked at the parts schematic for this heater, and saw not mention of or part# for a "dip tube". My heater Model # is SW12DE. If as stated, they are inside the tank, how could one possibly get in to replace them?


    It is EXTREMELY rare for the DIP tubes to come loose. They can indeed be replaced, but I have seen only one in 41 years as an RV tech. The purpose of the DIP tubes is to prevent COLD water mixing with the HOT water in the tank when you are using the WH. The COLD intake dip tube has a slight curve and points DOWN and the HOT water exhaust tube is the same but points up. You remove the HOT and COLD intake lines and 1/2 inch thread in adapter and slide the tubes in. BUT, with the 1/2 inch adapter removed, you can insert a very flexible plastic tube inside and feel if the tubes are still in place. They are usually dislodged when someone is working on the W/H and they insert a tool or thread the 1/2 inch adapter in too far and knock it loose. I DOUBT THIS IS YOUR PROBLEM. Have you checked the temp AT THE POP OFF VALVE? Doug
  • Old-Biscuit, Are you able to provide any more info on the dip tubes you mentioned? I looked at the parts schematic for this heater, and saw not mention of or part# for a "dip tube". My heater Model # is SW12DE. If as stated, they are inside the tank, how could one possibly get in to replace them?
  • Thanks, but the bypass valve was the first thing I checked. As for the other suggestions, all hot and cold faucets are off and regarding the dip tubes, I was no even aware of them. Will have to get some tools and investigate further.
  • By any chance did you partially open your bypass valve that is between the red and blue pipe?
  • Water Heater water temp measurements are taken at the outside POP OFF valve. If the temp is not 130/140 at the pop off valve then suspect the tstat or ECO. IF the temp is at spec, then check for bypass valves and such as the problem. Doug
  • If you have an outside "shower," make sure both of those valves are closed. If not, that faucet acts as a mixer and all you'll get is warm water inside.

    Rob
  • BB_TX wrote:
    There are two thermostats, one for electric and a second for propane. Not likely both with same issue.


    YEP^^^^
    The T-stats are under the 'Push to Reset' Cover above gas valve
    Left side is 120VAC for electric and Right side is 12VDC for propane

    T-stats Open at 130*F/Close at 100*F for heat cycle
    High limit t-stat trips at 170*F..manual reset via push button

    Where are you measuring the 108*F temp???

    If at a faucet....
    Check if shower H/C Knobs have been left ON and button on lever has been used to stop shower flow
    Shower faucet then acts like a 'mixing chamber' diluting Hot temps

    If not shower then could be one of the Dip Tubes has broken off inside the WH Tank
    Cold one point DOWN and Hot one points UP
    Either missing and cold quickly mixes with hot diluting the temp
    Drain/remove anode rod and use bright flash light to see in a plastic tube is laying in bottom of WH Tank
    Remove element to retrieve

    Replacement Dip Tubes are available
  • There are two thermostats, one for electric and a second for propane. Not likely both with same issue.