GG could you please send me a copy of the Vaillant 242 manual. I've just changed the DHW Heat exchanger for the new type, put a new Diverter on as that was passing. still having hot water probs(intermittent) looking at putting a new servo assy on next with diff diapragm. But need to know if my model is the hybrid and needs the link taking out. Thanks a lot.
Thanks a lot for the comments - if only I had spoken to you before choosing the boiler! I have finally managed to talk to National Grid again and have one of their experts who is looking into the plans for the house to see what size the service pipe is - we can then work out if we need a bigger one or if it might be blocked. He has also recommended a higher capacity meter.
You seem to the the expert on combi boilers and gas pressure and I have been round the houses and back again with everyone I can find (installer, Vaillant experts and Transco) to no avail. I wander if I may ask you a question. I have a vaillant 937 which has a low gas working pressure problem. The working pressure at the boiler is 12-14 and 16 at the gas meter after a new govener (sp?) was fitted. Transco say they are not able to adjust the govener (is this true?) and that the supply pipe to the meter is 22mm and needs to be bigger i.e. my garden, drive and footpath all need to be dug up.
Based on this very limited information can you let me know what you think as this is a lot of work and mess and I suspect Transco may not put my drive back in the condition it is now in.
If this really is the only route might it be cheaper to buy a new boiler and can you recommend one that will not have this problem - space is not an issue as the boiler is in the garage. I am reluctanct to have a hot water tank etc fitted as this is even more mess. We have a 4 bed, 2 bath house.
Really appreciate this.
hi guru can you advise me on a top central heating pump im off to get one today . i notice whikes doing them for 35 for a 5mm and 45 for a 6mm . also what does that mean. the 5mm and 6mm? i think whickes pumps are silo
The problem is that the system has an air lock, it is a mains fed boiler heating system (Butco) problem started when the water had gone off and as normal I turned on the hot tap and now it makes a continuous noise when the hot water tap is turned on slowly. Do you know what is causing it and how t fix it??
Always check the static/dynamic incoming water pressure and flowrates before contemplating an unvented cylinder installation. Be aware some street pressures drop considerably at peak times ie test at this time to avoid disapointment.
There are two basic types of cylinder, air bubble (bubble tops) eg the Megaflo and those having a seperate expansion vessel. Some external vessels are however hidden within the top casing of the cylinder.
The pressure reducing valve does not necessarily need to be installed alongside the cylinder..sometimes it is more convenient to place it under the kitchen sink. It is always worth fitting a pressure gauge into the reducing valve (they normally have a blanked port) to enable the set pressure to be checked on a regular basis. The gauge is also useful to indicate blocked inlet strainers or insufficent water supply problems.
Unvented cylinders must be maintained on a regualar basis (normally annual). The bubble must be re-generated or the expansion vessel pre-charge pressure checked (and re-inflated where necessary). Strainers, PRV setting etc should also be checked. Failure to service on a regular basis will lead to safety device activation leading to expensive repair costs. Manufacturers warranties are also invalid without a signed service schedule.
A 2 port zone must be used if connecting the cylinder to a conventional boiler. Solid fuel boilers must not be connected directly to an unvented cylinder.