Dodgy shower pump

[Robert Perkins]

I decided to check if the gate valve had broken so drained the cold water tank and hot water tank. Checked valves on cold and hot feed. They are fine. Checked pump filters. No issues. Refilled the system and now no issue with the shower turning on and off.

However I have a different issue now- no cold water in the shower. Just hot water! Any ideas why this may be the case ?

 

[just pumps]

I decided to check if the gate valve had broken so drained the cold water tank and hot water tank. Checked valves on cold and hot feed. They are fine. Checked pump filters. No issues. Refilled the system and now no issue with the shower turning on and off.

However I have a different issue now- no cold water in the shower. Just hot water! Any ideas why this may be the case ?

Run it on full cold for awhile and hold the shower head as low as possible if you can.

 

[Robert Perkins]

Run it on full cold for awhile and hold the shower head as low as possible if you can.

Thanks. Should I turn pump off for this? Unfortunately it's fixed into the wall so it's stuck high in the air.

 

[just pumps]

No, you want the pump running, as the head is fixed to the wall it may take some time for the cold to come through providing all valves are open

 

[Robert Perkins]

No, you want the pump running, as the head is fixed to the wall it may take some time for the cold to come through providing all valves are open

This didn't work unfortunately. Just very hot showers at the moment. The temperature doesn't seem to change at all so wondering if it could be a broken cartridge. Do you know how I can tell? It's a dual one so don't want to spend money on a replacement if it's not broken.

 

[Harry Bloomfield]

This didn't work unfortunately. Just very hot showers at the moment. The temperature doesn't seem to change at all so wondering if it could be a broken cartridge. Do you know how I can tell? It's a dual one so don't want to spend money on a replacement if it's not broken.

Just grasping a straws - might you have got the two cartridge mixed up?

Another guess - I would guess at the cartridges being similar to a waxstat, or a TRV head. A pin in the unit will change position as the unit is heated up, thus proving the unit is working. Popping the unit in a pan of very hot water should confirm proper operation.

 

[Robert Perkins]

Just grasping a straws - might you have got the two cartridge mixed up?

Another guess - I would guess at the cartridges being similar to a waxstat, or a TRV head. A pin in the unit will change position as the unit is heated up, thus proving the unit is working. Popping the unit in a pan of very hot water should confirm proper operation.

These are the two parts of the cartridge with the one of the right going in the back of the one on the left. It's like a waxstat? Thinking about dunking it in lemon juice overnight to see if it helps any potential limescale. Regarding the pin changing position is it the one on the right picture you are referring to?

 

[Harry Bloomfield]

Regarding the pin changing position is it the one on the right picture you are referring to?

I cannot help you there - All I can say is that the general principle of wax cartridges in temperature control, is that the wax in the cartridge expands as it heats up. There pressure of the expansion is then used to operate a valve.

With lots of use, the cartridges can fail and the wax leak out.

 

[Robert Perkins]

On more observation before I give up. Both sides of the shower pump seem to be hot and the little screw valve bleeds hot water on both sides. Also without the cartridge in i just get hot water coming out the void. Could this be an issue with the inside of the pump?