This sounds like an examination question but it really is a problem two different plumbers have been unable to resolve after spending several hours studying my hot water system. My flat has a vented hot water system supplying hot water to the kitchen and bathroom taps. The pump is a Stuart Turner type. There is, as you would expect, a cold water tank above the hot water tank. The cold water tank was refurbished by a plumber three years ago at which time a new hot water tank was installed. The pump was not changed as it worked fine and was several years old at the time the system was refurbished.
The system has worked well since it was refurbished until recently when both hot and cold water was stopped. A plumber was called and a new pump was fitted as the old one had apparently burnt out. A few days later and no hot water. The same plumber came back and diagnosed that a new flange was required which was fitted. A few days later, no hot water and the plumber revisited and diagnosed that the non return valve fitted to the pipework needed to be removed. A few days later, the plumber said that a senior plumber needed to inspect the system which occurred without any conclusion as to the actual problem. At this time, a Stuart Turner accredited plumber was invited to inspect and it was found that there was some insulation in the hot water tank which was causing a blockage in the pump. This was cleaned out and the plumber said that the hot water tank needed to be drained and cleaned out. This occurred today but the plumber left not understanding the reason why there is a fault. The fault being no hot water. Apparently air is somehow entering the system which has to be regularly bled otherwise no hot water.
I would appreciate any advice on what could possibly be wrong since two different firms have already investigated without any success, including a senior plumber.
The system has worked well since it was refurbished until recently when both hot and cold water was stopped. A plumber was called and a new pump was fitted as the old one had apparently burnt out. A few days later and no hot water. The same plumber came back and diagnosed that a new flange was required which was fitted. A few days later, no hot water and the plumber revisited and diagnosed that the non return valve fitted to the pipework needed to be removed. A few days later, the plumber said that a senior plumber needed to inspect the system which occurred without any conclusion as to the actual problem. At this time, a Stuart Turner accredited plumber was invited to inspect and it was found that there was some insulation in the hot water tank which was causing a blockage in the pump. This was cleaned out and the plumber said that the hot water tank needed to be drained and cleaned out. This occurred today but the plumber left not understanding the reason why there is a fault. The fault being no hot water. Apparently air is somehow entering the system which has to be regularly bled otherwise no hot water.
I would appreciate any advice on what could possibly be wrong since two different firms have already investigated without any success, including a senior plumber.