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Why does the pressure keep dropping on my Vaillant boiler?

7 Answers

Answered by Louis Gas & Heating LTD

6th April 2019

Louis Gas & Heating LTD answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

Loosing pressure is usually from a leak on your heating system. Other reasons could be loosing pressure from the pressure relief valve. This can be a number of reasons from over pressuring your boiler to blockage in your boiler from sludge or expansion vessel needing re pressurising.

Answered by Shisa Gas & Heating

23rd March 2019

Shisa Gas & Heating answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

1) check all radiators for leaks. 2) Find the copper over pressure pipe, most often on the outside wall near the boiler location. Top up the system and run the heating. If practical, place a small container to see if any signs of water from the pipe. Is so, then the expansion vessel needs to be recharged or has failed. It is likely that the over pressure valve will need to be replaced as well. 3) If you have been topping the system up regularly over an extended period then the inhibitor chemical in the system will be diluted and will need topping up. 4) If not 1 or 2 above then the leak is either in hidden pipework, the coil of the the hot water cylinder (if you have one) or within the boiler. 5) In all cases get a registered gas engineer to properly diagnose the fault and provide a suitable repair.

Answered by Kingston Gas Services Ltd

23rd March 2019

Kingston Gas Services Ltd answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

Loosing pressure is usually, one of the following: 1. A leak from a pipe, or radiator 2.A leak from the boiler, possible from the pressure relief valve which terminates outside 3.Sometimes from the plastic magnetic filter. If you have a pressure drop, have a visual check round the radiators, valves any pipes you can see, check the copper overflow outside near the boiler, or ring a professional engineer

Answered by HM Heating

15th March 2019

HM Heating answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

The pressure will drop for a a few reasons as others has said; 1/Low pressure in expansion vessel - this often can be identified with a steep rise in pressure when the heating is on and water coming from the prv pipe 2/a leak on the system or boiler I would advise contacting a local gas safe registered business who can assess and advise on the next course of action.

Answered by C Brookes Plumbing & Heating

3rd March 2019

C Brookes Plumbing & Heating answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

There can be a number of reasons for a boiler to lose pressure, this could be -The pressure relief valve on the boiler is letting by. -The expansion vessel may need re-charging or could have failed. -You could have a leak on the heating system somewhere To find the cause of the pressure drop its best to contact a gas safe engineer to take a look to find the cause of the problem.

Answered by Alltime Plumbing & Heating

28th February 2019

Alltime Plumbing & Heating answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

loss of pressure on the boiler could be one of the following faults 1. expansion vessel needing to be re pressurised. 2. a faulty pressure relief valve letting by or there could be a leak on the system. either way this should always be done by a gas safe registered engineer.

Answered by M&M Gas Services Southern Ltd

10th February 2019

M&M Gas Services Southern Ltd answered the question "Why does the pressure keep dropping on my Vaillant boiler?"

A couple of reasons for a pressure drop. a) the expansion vessel may have failed or lost pressure. b) the prv could be letting by. c) you could have a leak. d) a combination of all. Without a proper examination it is impossible to tell. If the components mentioned are inside a boiler, you would need to employ the services of a gas safe registered engineer.

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