Which is the one question to ask?

[diyblonde]

If there was one question to ask a plumber or central heating expert to gauge the depth of his/her competence what would it be?

I'm new to an area and don't have any references for tradesmen. Already have one botched plumbing job so I'm trying to find someone good to fix it and also trying to find a central heating engineer to fit new rads and central heating.

My theory is 'the longer someone works in a field of expertise the more well versed they become.' So there has to be a "definitive question" to ask, a "theoretical problem to pose" to a plumber which a rookie or chancer won't get right and the expert be able to answer without batting an eyelid.

Perhaps there are two or three questions to ask with varying degrees of complexity that will sort "the men from the boys"?

So can someone please tell me what those questions are!!!!!!

 

[lor]

ask him ,"tea or coffee" always works with me

 

[corgiman]

ask him ,"tea or coffee" always works with me

 

[diyblonde]

OK genius ...

but that kind of proves my point!

 

[Andy165]

There are some people round the north west who talk a great job, know the theory and have got the gab to price up jobs very nicely but then sub them on to the "workhorses" after taking their tidy cut. The usual applies, three quotes (plus one from bg for a laugh) and try to get a recommendation from someone local who has recently had some work done.

 

[diyblonde]

Thanks Andy .. so big firms are not always better? I've got one sending me a quote in the next couple of days and I'm sure it's going to be at least a grand more expensive than the "two man team" that came the other day. After a dismal plumbing experience I'm scared to make the wrong choice!

 

[Gasguru]

Well here's a couple of starters

Is it permissable to use a BS1212 Part 1 float valve on a F&E cistern?

Provide at least 5 reasons for loss of water seal in a typical basin P trap and how they can be prevented.

In relation to NPSH how can cavitation be avoided on a high head shower pump?

What is the minimum distance (from drain invert) for a stack connection in a typical domestic property?

Explain Maguire's rule.

Explain the operation of a type CA backflow device, its advantages/disadvantages and a common boiler model it is found on.

What is the recommended lead code for soakers.

In what application is it acceptable to use hemp in plumbing/heating.

What height should a soil stack vent to within 3m of an openable window.

Explain hydraulic gradients in regard to water takeoffs.

What is the typical expansion rate of domestic copper heating pipework.

Explain the advantage of close coupled feed and vent pipework on a heating system.

What advantage does a 2 pipe reverse return heating system offer.

What is the permissible drop on a domestic ultrasonic gas meter (appliances connected and no gas smell reported).

What is the working pressure (at the meter) and the tolerance allowed?

Why do fully pre-mixed burners on modern boilers offer lower NOX emmisions than their predecessors?

What advantage do radiator valves to BS2767 Part 10 offer and why are they essential on sealed systems?

What is the principle of Elson/Harton//Hydro Spartan setups in regard to primary water expansion?

In what application is it permissable to not fit a room thermostat to a new heating system?

 

[diyblonde]

Wow Gasguru consider me dazzled.



Dazzled but don't know the answers myself! Any chance you could answer a couple of those for me so I don't get tied in knots googling? I just need a tricky question or two that a pro would know ... so not something typically textbook that every learner plumber would have studied.

 

[sooey]

gasguru I know number 5, ask me, ask me

sh*t doesn't run uphill.

 

[Gasguru]

Well here's a couple of starters

Is it permissable to use a BS1212 Part 1 float valve on a F&E cistern? Yes providing it is fed by a double check valve.

Provide at least 5 reasons for loss of water seal in a typical basin P trap and how they can be prevented. Evaporation, wavering out, compression, self syphonage, induced syphonage etc.

In relation to NPSH how can cavitation be avoided on a high head shower pump? Using Surrey/Essex flanges, correctly sized pipework, fullbore isolating valves, using copper fittings (as opposed to pushfit), dedicated feeds etc etc.

What is the minimum distance (from drain invert) for a stack connection in a typical domestic property? 450mm.

Explain Maguire's rule. Drainage pipe diameter/2.5 gives the self cleaning gradient for intermittent or low pipe flows.

Explain the operation of a type CA backflow device, its advantages/disadvantages and a common boiler model it is found on. If backflow is encountered the intermediate pressure zone vents water from the valve. Advantages are a boiler filling loop can be left connected (up to 45Kw o/p), disadvantages are they leak when filling, leak if backflow occurs and a tundish is not plumbed in and the water main pressure needs to be somewhat higher than the cold fill pressure.

What is the recommended lead code for soakers. 3 but preferably 4.

In what application is it acceptable to use hemp in plumbing/heating. Long screws on steel gas pipework.

What height should a soil stack vent to within 3m of an openable window. 900mm.

Explain hydraulic gradients in regard to water takeoffs. Incorrect positioning of feed takeoffs can result in lack of flow to higher outlets.

What is the typical expansion rate of domestic copper heating pipework. 1mm/m lenght

Explain the advantage of close coupled feed and vent pipework on a heating system. Both pipes are at similar pressures eliminating pumping over/air entry problems.

What advantage does a 2 pipe reverse return heating system offer. Balancing is simplified.

What is the permissible drop on a domestic ultrasonic gas meter (appliances connected and no gas smell reported). 8mbar.

What is the working pressure (at the meter) and the tolerance allowed? 21 ±2 mbar.

Why do fully pre-mixed burners on modern boilers offer lower NOX emmisions than their predecessors? Flame height and temperature reduced lowering the production of thermal NOX.

What advantage do radiator valves to BS2767 Part 10 offer and why are they essential on sealed systems? The valve spindle has an addition seal preventing leakage and hence loss of system pressure.

What is the principle of Elson/Harton//Hydro Spartan setups in regard to primary water expansion? An self contained air bubble is compressed to absorb expansion volume.

In what application is it permissable to not fit a room thermostat to a new heating system? When the boiler contains for example a flow sensor eg the Potterton Promax

 

[chrishutt]

Gasguru, what a ridiculous set of questions! Do you seriously expect any practical working plumber to be able to answer more than a couple of those off the top of his head? I couldn't (half the questions don't even make sense) - does that make me incompetent?

Diyblonde, to address your question, it's a question of horses for courses. If the job in question involves refitting a bathroom then there's little point in expecting your plumber to be expert in gas fitting or roof flashing. Ask questions about the type of work you want done and see if the plumber appears to know something of the technical background to it and the practicalities of getting the job done.

 

[JohnD]

contact some other local householders he's recently done similar work for.

If he hasn't got any satisfied customers ask yourself why.

 

[PlanetThanet]

Hi

Ask, are you a member of IPHE and/or CORGI (and ask for their ID cards.)

Unfortunately having the gift of the gab is exactly how the rip off types make a killing.( Usually from the big yellow book.)
Quite a few people can suss out a dodgy character after a bit of conversation in the same way some of us can suss out dodgy customers.
Pretend you are playing poker,ie try not to give the indication you know absolutely nothing!

Thanet

 

[NickStone]

If there was one question to ask a plumber or central heating expert to gauge the depth of his/her competence what would it be?

One thing you might like to ask is whether the person actually doing the work will be Corgi registered and/or (depending on what you're having done) belong to the IPHE. I got caught out by this once after choosing someone from Yellow Pages (and you can stop laughing, guys - sometimes we have no choice). Anyway, the owner of the firm came round and seemed very competent. The guy who came to do the work was anything but. He thought he was, of course - and that's the worst combination: incompetence mixed with arrogance. He couldn't fix the problem and we had to get someone else.

Another thing you might want to think about is introducing a topic that's nothing about plumbing but which reveals the kind of person they are. For example, you could say something like, 'Sorry, I'm not thinking clearly today - had a bit of a skinful at the pub last night.' If he gives you a knowing smile or says 'I know what you mean,' you might want to give him a miss. Does he have a huge beergut? In my (admittedly limited) experience, the best tradesmen tend to be lean and fit because they work so hard. (This is not an exact science but you did ask.)

 

[ChrisR]

I'd take issue with a couple of GG's answers but I'm a fat bloke not in the IPHE so that counts me out.

You could ask how a bath would be fixed. The answer is a long one - it depends.
Ask what you'd need for a really good shower - how many options do they give.
Ask to speak to previous customers. SHouldn't be a problem. Ask them how long ago he worked for them - be suspicious if it's ages.

A friend just asked Dolphin for a quote for a pretty ordinary bathroom.
£24,000!
Ah, special dscount of 70% just for you
and he could magically get another 10%
2 - 3 grand would have been enough I would have thought, considering what they want.