Rinnai gas water heater temperature adjustment

[tstore]

Hi

 

I have a Rinnai gas water heater which does hot water for kitchen and bathroom. There are two flame settings, low and high. The low setting is fine in summer but no for winter. When on the high setting the water comes out taps at a scalding temperature. Its has a temp dial to reduce the temperature but this seems to have no effect in reducing the temperature.  Whilst I can handle this in the kitchen with the mixer taps, the mixer in the bathroom shower seems to be very fickle in controlling the temperature so you go from scalding, try to adjust to lower temp and then it goes cold for a while and sometimes recovers but mostly you have to turn it up to scalding again and try the process again. Any suggestions gladly accepted.

 

Thanks Thomas

[WotEver]

My guess would be that the pump flow rate is too low. 

[Arthur Marshall]

The temperature control knob just adjusts the water flow. The more water, the cooler. With mine, if I use the cold tap as well there isn't enough going through the heater so the flame goes out (cold water, turn off cold tap, Rinnai relights, scalding) so i have to regulate the shower temp purely by the Rinnai setting. If you can't cool it down your pump possibility isn't hefty enough to provide enough water, supply pipe may be too thin. 

[WotEver]

22 minutes ago, Arthur Marshall said:

supply pipe may be too thin. 

Or that too

[bizzard]

Non of the instantaneous gas water heaters perform very well with accumulators and such. They like to work direct from the pump, once controls are set with a steady pressure with the pump just going at a steady tick, tick, tick, tick, tick and not going on and off all the time with the pressure varying slightly all the time.

[Richard10002]

I have a Jabsco pump, an accumulator, and a thermostatic shower control. The shower temp is steady once set..

 

Took a while to get the pump pressure high enough to make the Rinnai fire up.

 

Previously had a mere mixer shower control, which was useless. The temp. fluctuated all over the place, and a shower was impossible.

[Boater Sam]

In this day and age we really should only use thermostatic shower mixing valves for safety reasons. The young and the old are particularly at risk of scalding.

All instantaneous water heater have the same drawback in that there must always be sufficient flow to maintain heating but not so much that the temperature drops appreciably. The amount of heat is finite, not so the water delivery.

[tstore]

HI all, I took the cover off the gas heater today and the spindle for the temperature control has sheared off. It was set on the maximum. Does anyone know if its possible to get spares for this model? I am going to get a thermostatic mixer in meantime.

 

 

[Dav and Pen]

I have one of these heaters on board. It came from Hamilton Gas in N. Ireland they would know about spares.

[Arthur Marshall]

On 05/03/2019 at 19:46, tstore said:

HI all, I took the cover off the gas heater today and the spindle for the temperature control has sheared off. It was set on the maximum. Does anyone know if its possible to get spares for this model? I am going to get a thermostatic mixer in meantime.

 

 

I'm sure I saw a thread about this happening a few months back. If they have improved the search function it may be findable. 

[Richard10002]

On 05/03/2019 at 19:46, tstore said:

HI all, I took the cover off the gas heater today and the spindle for the temperature control has sheared off. It was set on the maximum. Does anyone know if its possible to get spares for this model? I am going to get a thermostatic mixer in meantime.

 

 

Can you change the temperature by moving the stub, (pliers, mole grips, similar), to the temp you want? I set mine at 5 several years ago, and haven’t changed it since.

[tstore]

Thanks for the responses, I can't even see the stub so may need to take the thing apart, the metal rod appears to be connected the adjuster with plastic which as broken. I try contact Hamilton Gas in NI.