Combi or not?

[HumpyD]

Afternoon all.

We have a Potterton Profile boiler with a Gledhill Boliermate hot water tank. Both are just over 18 years old. A hole has appeared in the expansion tank on top of the Gledhill - about as big as a thumb nail and by the looks of it has been caused by corrosion. I have spoken to a few people who have said that as the hole is about halfway up the side of the expansion tank, the likelihood of water coming out is fairly slim. However, we still need to do something about it. So, what to do?

We are obviously going to need to replace the tank but I understand that a direct replacement for the Gledhill is expensive - @£1,200. Our concern is as the Potterton is 18 years old is it worth replacing this too as it's more than likely towards the end of it's life? (I should add the only only problem we've had with the boiler is the fan going about 4 years ago.)

Another alternative would be to replace both the boiler and the tank with a combi but I've read mixed reports about the reliability of these or whether it would be suitable for our needs. There are only 2 of us and we only shower so the need for lashings of hot water is not as great as some. Plus it would need to work the central heating.

Not sure if another option would be to simply replace the Gledhill with a less expensive tank - I understand the Gledhill is quite a sophisticated tank but I'm not sure whether we need this level of sophistication. Is this an option or would it involve a lot of work to plumb in? If we were to do this would it be worth replacing the Potterton at the same time?

I'm currently waiting for some plumbers to come round to give me their thoughts/prices, but I thought I'd put the question on here in the meantime.

Thanks.

 

[bengasman]

Any boiler, combi or not, is as good as the combination of the boiler itself, and the installer that fits it. If one of the 2 is lacking quality, you are likely to have problems.
Apart from a very rare occasion, maybe 1 every 2 years, I only fit comibi's and they have been extremely reliable.
Proper job cost a few bop though.

 

[Deleted member 105431]

Any boiler, combi or not, is as good as the combination of the boiler itself, and the installer that fits it. If one of the 2 is lacking quality, you are likely to have problems.
Apart from a very rare occasion, maybe 1 every 2 years, I only fit comibi's and they have been extremely reliable.
Proper job cost a few bop though.

what he said.

btw gledhill boilermate's aka sludge buckets are crap-get rid asap.

 

[mickyg]

I would recommend measuring your current hot water flow rate to see what you have. Your current system has potential to deliver a high flow of hot water, which may only be matched by a very few high end combi boilers.
Nothing worse then ending up with worse performance than you started with.
Also your current boiler, although old could well last for many years yet, as its one of the best wall mounted boilers ever produced. Simply replacing the tank with an unvented cyinder might be an option.

 

[obiplumbkinobi]

Gledhil are less than useless, tried to get replacement for a System mate 170, "straight swap" they said,was it ballcocks. Mickyg was bang on the money with his advice the choice is between unvented or a thermal store. there are always pro's and cons

 

[HumpyD]

Thanks for all the responses; very helpful.

Couple more things - how much (approximately) would it cost to fit a combi?

If I were to go down the route of simply replacing the Gledhill with an unvented boiler, what would the approximate costs of this be?

 

[GeorgeBramwell]

Gledhill's are fine and give mains pressure DHW. I know of many that are quite old and doing well. Your is 18 years old and still going well. The best thing you can do is plug up the hole with an Essex flange and a brass plug. The system is working so leave it alone until you have major problems.

If you have a future problem with the Gledhill or the boiler then consider a high flow combi. ATAG 51kW, floor mounted W-Bosch 550, or a 42kW W-Bosch at a push or again at push an Avantaplus 39C combi.

Is the CH run off the Gledhill? I would fill it with inhibitor, if not topped up, 3 or 4 1 litre cans for the average system. How many shower or baths do you have?

 

[HumpyD]

Hi George.

We had a plumber round earlier and he suggested putting a small plastic or metal plate over the hole and fixing it with LSX.

He wasn't unduly concerned as the hole is sufficiently high up on the expansion tank that water shouldn't get past it.

The CH is run off the Gledhill and we have 2 showers and 1 bath in the house. (One mainbathroom and an en suite.) Stupid question but what is inhibitor, what does it do and where do I put it (polite answers only please!)?

 

[GeorgeBramwell]

Hi George.

We had a plumber round earlier and he suggested putting a small plastic or metal plate over the hole and fixing it with LSX.

He wasn't unduly concerned as the hole is sufficiently high up on the expansion tank that water shouldn't get past it.

The CH is run off the Gledhill and we have 2 showers and 1 bath in the house. (One mainbathroom and an en suite.) Stupid question but what is inhibitor, what does it do and where do I put it (polite answers only please!)?

Drain the Gledhill and CH system. Put in system cleaner, run as per makers instructions. Drain, flush system, and fill up with 4 cans of Sentinel X-100. Can be bought for £40. Pour in header tank on the Gledhill as it is filling. If the header tank on the Gledhill is kaput, as separate plastic tank can be fitted connecting to the existing pipes to the cylinder beneath.

The whole Gledhill/boiler system is very efficient. There are ways of improving efficiency, but you need to know what you are doing in control.

 

[mickyg]

Sentinel X-100. Can be bought for £40.

I bought 6 bottles for £20 at the carboot sale on sunday
Everytime I go up there there's builders offloading plumbing gear they've been hoarding, guess they need to find a new source of income

 

[Paul Barker]

My advice would vary depending on which boilermate it is. Least electronic the better in my book. Sounds like yours is least electronic as it hasn't been any bother for 18 years.

As mentioned already the leak is a doddle to fix, I would go the replacement platsic f/e tank option.

You could just put a totally reliable band A regular boiler on the system. Most manufacturers' regular boilers are totally reliable these days.

 

[GeorgeBramwell]

Gledhil are less than useless, tried to get replacement for a System mate 170, "straight swap" they said,was it b*****s. Mickyg was bang on the money with his advice the choice is between unvented or a thermal store. there are always pro's and cons

I have come across many Systemates and all have been fine. What was wrong with it? Part are easily to get. Only one can of inhibitor is needed in the cylinder, as the cylinder water is separate from the CH system water, so no sludging if not fitted properly. They are a DHW only thermal store as the CH is not taken off the cylinder. What was the problem? I look after a 145 litre version serving two baths and two showers in a house with students in. I thought it would struggle and showers would need to be staggered. Not once has it ran out of DHW. The recovery rate is superb using a very large coil, and the DHW takes priority over CH and the CH pump is only switched in when the cylinder store temperature is above 60C.

It is a shame it is not made now and a suitable replacement is probably a Range thermal store using a plate heat exchanger (they have immersed coil versions as well). I keep an eye on replacements in case, then I do not have to hunt around and know the ideal product to buy immediately.

 

[HumpyD]

Morning all.

Woke up this morning and there is water dripping out of the hole!! Doesn't see too bad at the moment but I wondered why it has suddenly started to happen. Could it be anything to do with the fact that the heating has been working overtime due to the cold spell?