Worcester 350 Heat exchanger / Gas valve : Hot & cold wa

[nv_london]

I have a Worcester combi 350 boiler and I'd like to de-scale my secondary/water to water heat exchanger as I'm having problems with intermittently hot and cold water from the shower (and after a lengthy process of elimination, I believe this to be the culprit).

After reading the instruction manual, the removal of the heat exchanger seems relatively straight forward and logical (and I used this same manual a year or so ago to remove and replace the water pump, so I’m confident in my ability to carry out such tasks).

In order to get to the heat exchanger I have to remove the gas valve (I’m well aware of the associated risks/danger, so please, no comments on that).

Please see associated image(//www.diynot.com/network/nv_london/albums/)

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My question is, where/what is the cover of the main solenoid? And which is the lead of the Modureg head?

(By trial and error, I’m sure it’s quite obvious which screws hold the cover in place and which is the correct lead, but I prefer to know these things in advance).

Thanks for any help.

 

[Agile]

Common sense and the forum rules dictate that we cannot give advice on this public forum on DIY gas work.

The obvious advice is to get a local boiler engineer to remove and refit it for you.

Tony

 

[nickso]

the PHE will come out without removing the GV. tightening the top nut enough on re-fitting may be a problem though.

you have interpreted the instructions incorrectly anyway.

 

[nv_london]

Thanks for pointing out the rules Tony.

I've now decided against attempting the work myself but will instead call out an appropriately qualified engineer. However, due to work commitments I won't be able to call them out until next week, so in the meantime, could anybody quench my thirst for knowledge and answer the original questions? (Remember, I won't be attempting the work myself).

 

[nv_london]

Thanks Nickso.

I too thought the heat exchanger could be removed without removing the gas valve, but strangely, that's not what the instruction manual says. (Maybe, the instruction manual states the ‘best/most practical’ way of gaining access to the heat exchanger rather than the ‘simplest/more inconvenient way’, i.e, if one doesn’t remove the gas valve then gaining full access to the heat exchanger may be rather difficult, hence, your concerns with tighten the top nut).

(Following on from this, from reading the literature, I believe the gas valve needs to be removed to allow access to retaining clips holding the exchanger in place, which would otherwise be difficult to locate and remove...but I may be wrong about this).

Oh, by the way, could you please elaborate on how I incorrectly interpreted the instructions? Thanks.

 

[nickso]

the clips are accessible, just.

i actually made my own tool to tighten the top nut....in a completely professional manner i cut the end off an old spanner i've since mislaid it though. TBH, for a professional it's almost as quick to remove the GV as it's only ten minutes.

without going into details you have misread what needs to be removed.

 

[nv_london]

Hi nickso,

after re-reading your first post, I've now noticed that you mention removing the PHE however, my original post was concerned with removing the secondary/water to water heat exchanger, as by all accounts this is probably the culprit for the intermittently hot and cold water.

(Is this the reason why you stated that I’ve misread/misinterpreted what ought to be removed? – As the manual quite clearly states that in order to remove the water to water heat exchanger of a Worcester 350 includes removing its gas valve).

 

[nickso]

sorry, i mean plate heat exchanger by PHE, i can see why you mistook it though.


regarding the misread instructions, you have misread what needs to be done on removing the GV, i'm not going any further into it as i don't believe you are competent enough to do it.

 

[nv_london]

LOL @ mistakenly being called incompetent!

Anyway, like I said nickso, you can tell me as I won't be attempting the work myself but rather, calling in a much more 'competent' professional.

 

[kevplumb]

Anyway, like I said nickso, you can tell me as I won't be attempting the work myself but rather, calling in a much more 'competent' professional.

well you don't need to know then

 

[ollski]

LOL @ mistakenly being called incompetent!

Anyway, like I said nickso, you can tell me as I won't be attempting the work myself but rather, calling in a much more 'competent' professional.

To be fair nv you weren't called incompetent, just not competent to do the task which you stated yourself in the first post. 'trial and error' around the gas valve isn't wise as tiny adjustments to the modureg can lead to massive problems with combustion. Lots of tasks are dead simple to do from the manufacturer's instructions the gas valve requires additional skills it doesn't cover.

Have you measured the in / out temperatures of the primary water on the plated hx?, I get infinitely more sensor problems on a 350 than blockages.

 

[nickso]

LOL @ mistakenly being called incompetent!

Anyway, like I said nickso, you can tell me as I won't be attempting the work myself but rather, calling in a much more 'competent' professional.

i didn't mistakenly call you incompetent, i deliberately said i didn't believe you to be competent.

not falling for that old chestnut either, nice try though.

 

[nickso]

LOL @ mistakenly being called incompetent!

Anyway, like I said nickso, you can tell me as I won't be attempting the work myself but rather, calling in a much more 'competent' professional.

Have you measured the in / out temperatures of the primary water on the plated hx?, I get infinitely more sensor problems on a 350 than blockages.

a good point.

hope it isn't the PHE blocked cos if it is a leaking backplate isn't usually far behind.

 

[nv_london]

Boys, you’re getting sidetracked!

Kevplumb : Like I said, I want to know as I have a thirst for knowledge (however, I won't be attempting it as it's against all rules and regulations and laws and by-laws...any others Tony?).

Ollski : I never said I wasn't competent in my first post...which was all to do with the identification of parts....that was it. (Competency and inability to identify parts are intrinsically different things). Also, I was never even contemplating adjusting the modureg!

Nickso : I like you but you as with Ollski you can't judge an ability/inability to carry out a task (i.e. competency) by an inability to identify parts..which is what my first post was all about!

By the way, while I’m not registered I am in fact highly competent (as demonstrated when I successfully changed the water pump, expansion vessel and cleaned out the low pressure sensor on this 350. So, rather than incompetent I believe you’re referring to ‘not registered’ or any other term which would legally allow me to remove the gas valve.
You see, even if you thought I were extremely competent (which I am), I still couldn't carry out this work as I'm not registered! So, as I stated before, I take your point Tony and I won't be attempting this myself - not because I'm 'not competent'/'incompetent' but rather, because I'm not registered!

Thanks for all your help!







Through

 

[nickso]

well fair enough.

if you want to learn how the GV comes out you will have to watch the RGI do it, the best way to learn after all.