no CH, have HW, Pump scolding, pilot will not light!

[jonajuna]

hello all
i've searched through and found similar problems but not the same, so forgive me if i ask a basic question!!

system as follow:
potterton prima b boiler,
HW tank upstairs in airer, air splitter tank thingy, header tanks in loft directly above,
myson SMC SD53 pump and,
Honeywell V4073 diverter valve.

problems as follows:

while back (few weeks) lost all CH, local CORGI plumber diagnosed faulty diverter valve, quoted £160 for new valve (plus labour and full system drain??). i knew this couldn't be right so paid his call out fee and sent on his way. duly ordered and fitted new honeywell valve etc (£60 plus cussing), system had no leaks, valve all working fine (internals zipping back and forth according to HW/CH off or on at controller). feeling happy with self and strutting as man of the house (me big man and can fixum )

then.... within a few minutes....... pump not seeming to work, no real noise and very very hot to touch, hotter perhaps than surrounding pipework, valve working but again no heating in house, much confusion and cussing again. then the whammy! pilot light noted to be out, "mmmm" i thinks, "its not windy! why has that happened?" jumps up on kitchen chair to relight... click click lit, wait turn knob, pilot goes out???? tries again.. same thing, wait a while same again!

aargh! now sat here very cold, feeling daft, wife is sulking and we have no heating or water (have put on immersion for HW at least so wont smell).

why is this?
was the origional problem misdiagnosed?
i think the valve was stuffed as it didnt seem to be working like this one is (ie you can hear it turning back and forth according to the settings, the last one wasn't doing that...it would turn off CH but not turn it on).
has the pump gone too? was this the real cause or is it just coincidental?
the pump is 10 years old but the valve was replaced (by previously said plumber) about 5 years ago.

any help gratefully received!!! you may well save my marriage!!

(ok well not really, shes forgiven me worse things than being a crap DIYer!)

regards Jon

 

[DUAL-FUEL]

Did you drain down the system. Is all the valves open. Bleed the water pump, is the water coming out..

 

[jonajuna]

didnt drain down system, isolated as much as i could and then just drained the header tank and what was left in surrounding pipework.
all valves are open,

how do you bleed pump? cant see any means of doing that?
do you use the screw on the front marked (in event of pump lock...) ??

btw, you guys work fast! thanks for the prompt reply!!

 

[dave18]

From your description of a very very hot pump I would say that your last words in brackets is the answer to your problems,

"In event of pump lock"

turn off heating system undo screw with above markings some water will come out be careful it may be hot.

insert screwdriver into end of shaft and twist back and forwards until shaft will turn easily

replace plug turn on heating system and check that pump is running.

If not try again with the system turned on, but be ready to remove the screwdriver quickly when the pump starts as they turn at very high speed.

if this does not work it may need a new pump.

once the pump is working the pilot should relight and every thing should work normally.

 

[jonajuna]

screw will not come out! have investigated this following the last post

i undid the screw as far as it would go, you then have to pull out the screw until it "engages" with the spindle (did that) i then (as instructed on pump) turned the screw (and presumably the pump inside as it had got "heavier") repeatedly tried other direction too, put it all back as normal and tried to resart system....still wont light


so it sounds like i need a new pump then does it?

if so is this coincidence ? or have i done something to stuff it during my diy (but dont tell my wife if this is the case). or, even, was this possibly the root of the problems anyway?


thanks again for all your help

 

[dave18]

I think there are two problems here

1, is the pump now working?

2, I am not familiar with this boiler but would suspect the following has happened, you changed the 3 port valve and everything worked ok, then the pump stoped working with the boiler still firing I would say the next thing that happened is an over heat switch has tripped and this will need resetting manually (check in your instruction manual this will tell you where it is and how to reset it)

MAKE SURE POWER IS DISCONNECTED BEFORE RESETTING TRIP LIVE TERMINALS AT 230 VOLTS.

 

[jonajuna]

will check on the trip switch issue...will have to find the manula first!! do you mean the manula for the pump (dont have one) or for the boiler? which i dont have but a copy of this one ( which is the sister model to the primaB )
here

ah! have just reset the trip switch!!!

have fired up the system and will report back shortly!

it may be tomorrow now as i am very tired with all these headaches!!!!

many thanks for all your help guys! never knew this forum existed until this evening!! i will be a regular i am sure

 

[ollski]

are you getting 240v at the pump?....I would guess you lost the connection in the wiring box when you wired the valve in.

 

[dave18]

Just looked on the potty web site overheat reset switch is beside main thermostat control knob just push in with your finger then relight pilot and check the pump is running.

If pump not running check you have 230volts at the pump connections.

if no 230 at pump check your wiring in box where you changed your valve wire may have come out of terminal strip.

If you have 230 volts at the pump try freeing it off again if that does not work it looks like a new pump

 

[jonajuna]

the pump is doing something so i guess it is getting power? too tired to go and fiddle with leccy now... will die!

however i suspect the pump is knacked! i undid the screw i mentioned earlier for "unlocking" the pump to do the "screwdriver spinning" test (without the screwdriver just with the screw) and although i can feel some vibration through the screw i was expecting it to spin? it didnt!

also despite the ambiant temp being lower than the thermostat setting, the boiler has now shut down! the pilot is still lit though so that problem is sorted!

how many wires from pump to wiring box? i didnt look earlier (well did but didnt take any notice?!) im guessing just the straight up pos/neutral/earth. it wouldnt even be vibrating (and getting very very hot again) if the wiring was disturbed, would it?

 

[jonajuna]

thanks dave18, im fearing that too! another £60

and im meant to be saving my pennies for Glastonbury!!!! thatll be another 20 pints im short that weekend!

 

[ollski]

boiler has shut down on boiler stat because the water in the heat exchanger isn't going anywhere. The pump is wired in L,N,E with the boiler in the wiring centre. If your pump was airlocked and you let it spin long enoughit will have destroyed the bearings and need replacing.

 

[jonajuna]

mmm that is a possiblitly Ollski! for my future reference, how would you go about ensuring the pump doesnt become air locked in this sort of situation (ie changing the valve/ pump itself!)

many regards Jon

 

[jonajuna]

right!! got loads of air out through that screw on the pump. have twiddled with the "unlock" function and ?seems? ok.

have bled all rads (although no air seemed to be present)

DHW working fine

pump sounds as though it is working so presuming power is present.

rads are stone cold! and so are we

further suggestions or is it change pump time

 

[dave18]

As pump appears to be working as you say the DHW is OK I would check two things

1, is the room thermostat turned down too low

2, move the manual lever on 3 port valve to the manual position and lock it in this position. does the heating now work?

The heating must be working if the pump is working as there is nothing to stop it from working.

if heating now works there must be something wrong with the wiring of the valve.

If there is no heating then I think it must be the pump, is the pump still getting very very hot or is it about the same temp as the pipes?