No Hot Water from Shower/Problem since bathroom refit in May 2021
Anonymous user 28/02/2024 - 4.02 PM
Our mixer shower was fitted initially in May and within a few days, the cold water supply from the shower stopped and it was just boiling hot all the time. We thought it might have been an airlock because the valve/bar controlling the shower temperature kept getting stiff like there was pressure behind it.
A second plumber came out and connected the cold water supply only to the mains, but now we have just cold water in the shower and no hot. The basin in the bathroom has both. I've asked the plumber why we had only hot in the shower and now only cold water, and he has said this is because the cold water supply is stronger than the hot water supply and is overpowering the hot. He said the pressures need to be equal for both temperatures, but this doesn't make much sense to me as we had hot water at a good pressure and now cold water at a good pressure- we have just never had them together. He says the only solution is to get a pump fitted for hot water at a cost of £400-£500
Are you a tradesperson and able to answer this question?
Is the fitted shower brand new? Is it for low or high pressure system? Was it fitted correctly: cold on the right and hot on the left? If the shower is for low pressure system only, then second “plumber” shouldn’t connect it to the mains as this may damage the shower valve. This need to be investigated more.
Thx Rad
Hi, your shower head will be too close to the storage tanks in your loft (within 600mm) the only solution is to fit a universal pump. You can get them from screwfix for £350.
Answered16 September 2021
0
Anonymous user
Sounds as though you may have low pressure hot and high pressure cold. You need to make sure the pressures are balanced and that the shower fitted is suitable for either low of high pressure systems bearing in mind a pumped system is not seen as high pressure.
Most showers these days are thermostatic and most of them require balanced pressures. They work fine on combi systems because your pressures are virtually the same. If you have a gravity hot water system, you have two choices. The best option is to take the cold water feed from the domestic header tank and the hot from the cylinder and run them through a twin impeller pump which will give equal pressure to both hot and cold. The other option is to put a single impeller pump on the hot from the cylinder and take the cold from the main and install pressure reducing valves on both feeds after the pump to balance the pressures. This method is not as reliable as the cold mains pressure can sometimes vary at different times of the day which could then affect your cold water pressure even with the pressure reducing valve. The best way is tank feed both through a decent quality pump of 1.5 to 3.0 bar. Also, the pump needs to have a dedicated supply from the cylinder either through an “S” flange or an Essex flange to avoid air getting to the pump. If air gets to the pump it will initially be noisy and will fail in not much time at all.
