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Vokera Compact 24 Combi - very low DHW pressure - help!!!

Discussion in 'Plumbing and Central Heating' started by jsstevenson, 6 Apr 2006.

This topic originated from the How to page called Problems associated with noises from the central heating system.

  1. Gasguru

    Gasguru

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    Flow restrictors are fitted to most combi's to limit the water throughput with varying inlet pressures and tap outlet settings. It helps prevent the manufacturers from being inundated with phone calls from users that can't get their water sufficiently hot (especially 3/4 bath taps). Users often don't understand the boiler can only raise the water temperature to the required amount providing the flow rate is not too great.

    Unfortunately the restrictor also acts as a very good filter (so they block easily) but the O ring also becomes contaminated and gradually swells and blocks the restrictor.

    You can use the flow valve under the boiler to limit the flow if too excessive.....but sensible operation of the tap outlets is normally sufficient.
     
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  3. andynumpty

    andynumpty

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    Hi, thanks for the reply.
    So do you recommend removing the restrictor?
     
  4. colinc57

    colinc57

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    i did this "repair " on the boiler in the annex....however notice that as trhe shower is being used more at moment it sometimes runs hot then cold- so should I replace the resistor OR is it just that the boiler will never be able to run consant warm water
     
  5. imtoolman2

    imtoolman2

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    Hi folks, im having a problem with my vokera boiler, as has been described in ths thread i also had bad flow rate soon after fitting my boiler, the guy who did the work new exactly what it was due to fitting plenty of them before, and set about removing the flow resistor.

    my problem at the moment is that my radiators are not heating up enough to make the house warm, i have turned up the dials on the front of the boiler to the maximum settings and played around with my thermostats on the radiators but to no avail

    the boiler seems to be running fine and im not getting the red light or anything, still getting hot water although that has never been great.

    i use the towal raiator as the bypass for the system due to all the other rads having trv's on them so as a result that is usually scalding hot , but at the moment it is no where near as hot

    any ideas on what it could be ?

    thanks in advance

    Paul
     
  6. HarrogateGas

    HarrogateGas

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    This is a common problem on the Compact. I have come across this once and never got to the bottom of it (forunatly the boiler was being replaced for an unvented system) but it was just as you describe, very poor heating flow. I had the boiler stripped looking for a blockage but never found one.

    The fault with heating on Vokera Compacts is well documented here but none has ever solved the problem yet...........good luck and keep me posted if you sort it out. Im inrigued to know what you find.
     
  7. imtoolman2

    imtoolman2

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    Hi again guys, to i had a guy out to look at my Vokera 28 compact, as i mentioned above i have been having difficulty getting my rads to heat up enough to keep the house warm, and in this climate is proving a right royal pain in the ar53.

    so after making sure all my rads had been bled and all the TRV's free'ed up, the guy stripped down the boiler , he checked the pump and it was spinning when on and also the flow pipe was scalding hot when the heating was on, it certainly puzzled him and he opened up the heat exchanger compartment and had a poke around but couldnt think what was causing it.

    hes is a friend that does all my gas work ect but just asked me contact a boiler engineer and he didnt have a clue.

    after he went i decided to drain the system and fill it up which went fine, i bled all the rads again and switched on the boiler.

    it did the same as before started pumping the water round and then stopped....mmm so i decied to time what the boiler was doing
    for 1:25 it fired up and was pumping the water round and then stopped for 3 minutes heating and kept pumping, it continues to do this cycle and because of this the rads arnt getting up to a workable temperature

    i just though i would add this just incase someone knew if there could be a thermostat or sensor that would cause this behaviour and perhaps would know how to fix it as im bloody freezing


    thanks in advance
    Paul
     
  8. imtoolman2

    imtoolman2

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    Ok folks i just thought i would let you know that i have solved my problems with my heating, as previously said my rads were not heating up to a usable temperature, basically the heat exchanger was firing up and heating the water and the pump was pumping it round, the thing was that the flow pipe was scalding hot and the return stone cold and the boiler would only stay on for 1 minute 25 and the switch off for 3 minutes and the back on again,

    i spoke to a heating engineer today and he said that the silver braided hose coming from the heat exchanger would be blocked and i should remove it an clean it out.

    so i stripped it off this morning and loan behold it was blocked solid with build up, it took around 25 minute with a long screwdriver to break up all the deposits and clear the pipe again

    stuck it back on and the whole house is now boiling again.
    thank god

    just thought i would let you know as it might help someone else out

    cheers
    Paul
     
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