Advice required for unvented system

[Cello]

For the first time, I have moved to a new house fitted with an unvented system so I have no experience of this type of system. An engineer is booked for tomorrow for an annual service and I would just like advice on what he should do during the service so that I can be sure that it has been done properly. It's a Worcester boiler, a Therma Evocul cylinder and there are two expansion vessels, one white and one grey. Many thanks.

 

[Riley]

Trust your engineer we aren’t all out to scam you

 

[ShaunCorbs]

Agree with the above but in short

Check every thing is working and correctly installed
Clean any filters
Re check any vessels
Check the hot water temp
Check the heating temp

Might be worth getting him to service the boiler as well

 

[chris watkins]

Well that took me all of a minute to find, some people just don't want to read anything any more.
P.S. if you have the internal expansion cylinder you will need to down load (or pick up) the Manufacturers Instructions yourself. I bet the service engineer can't wait to meet you Cello!!

ANNUAL SERVICING

A competent installer should carry out the following checks on an annual basis, ideally at the same time as the annual boiler service.

1. The expansion relief valve on the inlet control set should be eased open allowing water to flow for 5 seconds. The valve should then be closed making sure it resets correctly. Repeat this procedure with the pressure / temperature relief valve. Always insure that the discharge pipework is allowing the water to drain away adequately. If not check for blockages etc. and clear.

2. Ensure that any immersion heaters that are fitted are working correctly and that they are controlling the water at a temperature of between 55°C and 60°C.

3. Make sure the pressure in the expansion vessel is charged to 3 bar. Turn off the water supply to the unit and open a hot tap first. The valve on the expansion vessel is a Schrader (standard car tyre) type. Air or CO2 can be used to repressurise the expansion vessel.

4. Remove the head on the inlet control set by unscrewing, and clean the mesh filter within.
5. The benchmark service record supplied within this manual shall be updated at each service by the installer.

SERVICING

SERVICING MUST BE CARRIED OUT ANNUALLY & SHOULD ONLY BE CARRIED OUT BY COMPETENT INSTALLERS AND ANY SPARE PARTS USED MUST BE PURCHASED FROM US. NEVER BYPASS ANY SAFETY DEVICES OR OPERATE THE UNIT WITHOUT THEM FULLY OPERATIONAL.

YOUR GUARANTEE MAY BE VOID WITHOUT PROOF OF ANNUAL SERVICING. THE COMMISSIONING CERTIFICATE SUPPLIED AT THE REAR OF THIS MANUAL SHOULD ALSO BE COMPLETED BY THE INSTALLER.

 

[Welder]

For the first time, I have moved to a new house fitted with an unvented system so I have no experience of this type of system. An engineer is booked for tomorrow for an annual service and I would just like advice on what he should do during the service so that I can be sure that it has been done properly. It's a Worcester boiler, a Therma Evocul cylinder and there are two expansion vessels, one white and one grey. Many thanks.

I must echo my fellow professionals. The fact that the media portrays our profession as they do is utter nonsense in my experience. The heavy irony of using a plumbers forum to check up on your plumber is not lost!

Have you told the plumber they are there to service an unvented cylinder? If you haven't specifically told them that, they may not be G3 registered and therefore cannot do it. If you haven't specifically done so, because few are really, may I suggest you call him asap to explain and potentially not waste anyones time or, indeed, money.

If he turns up and cannot do as you have asked because you never gave him appropriate information, then you are, rightly, liable for his costs of attendance.

 

[Cello]

I did not mean to question anyone's professional integrity and apologise if anyone felt affronted. In the case in question, the engineer did a superb job. Many thanks for all the helpful comments.