Heat only boiler with unvented cylinder

[busydad]

Hi all.

Following my recent threads, my boiler has now been written off and I am now obtaining quotes for a new boiler and unvented cylinder.

I've had a good quote today, however I have been quoted for a heat only boiler. I thought a system boiler would be more appropriate for an unvented system? Do I need to be concerned or might this be fine depending on the set up?

Basically what are the pitfalls with using a heat only boiler in this scenario?

Many thanks

 

[muggles]

There are no pitfalls to using a heat only boiler, save for the make and model chosen, and the tendency for some manufacturers to offer shorter warranties on Heat Only boilers for no good reason. A little more detail about your quote might help if you'd like more advice though...

For what it's worth, I'd spec an Intergas boiler, and a Joule Cyclone cylinder

 

[busydad]

Basically it is for a 210l unvented tank (doesnt state which), with a Baxi Ecoblue Advance 19 heat only boiler, with smart thermostat system fitted (I am querying which). We have quite a big house (5 bed 1 bath, 2 ensuite with around 15 rads I think).

I imagine some changes to pipework needed as we currently have a heat only boiler with a Gledhill Systemate 2000.

Quote comes in under 3k (and the price is fixed), which seems pretty good. It's not all about the money though, a good job with reliable products is the most important.

 

[ianmcd]

seems overly cheap to be honest, the baxi Ecoblue advance is a decent boiler though

 

[busydad]

Thanks, it was cheaper than I expected. For a lay person like me it is hard to determine who is going to do a good job. I have a plumber/gas engineer who I have used for years but he can't fit unvented systems so i've had to rely on sites which give ratings/reviews. He did ask me which boiler make I was after and I asked for Baxi. One of the other gas engineers who came round said he wouldn't touch Baxi with a bargepole (they install Vaillant only). Each to their own I guess!

I'll check what type of cylinder he plans to install.

 

[FiremanT]

I can't remember what space is available. Overall, a system boiler will be more compact.

I am a Baxi fan, as are the majority of local,installers that I know. I think it is largely what one (as installer) is used to.

If one has to phone Baxi technical, you normally get a quick and helpful response. I tried to phone Ideal today. It just kept cutting out

 

[busydad]

OK he got back to me - the cylinder is a Telford Tempest - stainless steel if that means anything to anyone. I've had a quick look - only a 2 yr guarantee on the components (lifetime on the tank itself). Slightly concerned or am I reading far too much into this?

Just beginning to wonder if I should just replace the boiler and keep the Systemate 2000. The only real problem with the latter is that it has two leaking pump valves, but could get these replaced.

 

[Dan Robinson]

only a 2 yr guarantee on the components (lifetime on the tank itself). Slightly concerned or am I reading far too much into this?

That's standard.

Joule is a better cylinder though.

 

[busydad]

Thanks- in what way is the Joule better? (quality / efficiency / reliability?). I don't know much about cylinders. I obviously want a decent one in terms of reliability and efficiency, but wouldn't want to pay through the nose for it.

 

[Dan Robinson]

There's little in it to be fair, but the outer shell is a better quality and the connections are standard compression rather than having to use male irons.

I hear the Baxi is a decentish boiler, but like Muggles, I would always go for an Intergas.

 

[muggles]

Thanks- in what way is the Joule better? (quality / efficiency / reliability?). I don't know much about cylinders. I obviously want a decent one in terms of reliability and efficiency, but wouldn't want to pay through the nose for it.

There have been some instances in the past of customers with Tempest cylinders complaining that the heating coil is noisy, so that every time their hot water is heating they can hear the water flowing round. I think it's to do with the way the coil is (or isn't) supported inside the cylinder. Don't know whether Telford have drove anything to address this.

The Baxi is OK, but it's not compatible with the most efficient heating controls (OpenTherm and Weather Compensation), and its modulation range (the difference between maximum and minimum output) is very poor, so real-world efficiency isn't as good as others on the market. If you want a smart thermostat, buy a smart boiler to go with it, otherwise you rather defeat the object.

It's not capable of taking full advantage of the rapid heat recovery offered by an unvented cylinder either, and an aluminium heat exchanger means that it's more sensitive to corrosive conditions than boilers with either copper-lined or stainless steel heat exchangers. The latter can be dealt with by ensuring inhibitor levels are kept high.

Hope that helps

 

[busydad]

Thanks Muggles - you are very knowledgeable.

Just to update I was a little unsure about the cylinder therefore I have decided, for now, just to get my boiler replaced and probably look to put a cylinder in next year when I can have time to make a considered decision as currently under pressure to get something sorted.

I did end up going for the Baxi, so I will make sure the installer adds plenty of inhibitor. I appreciate what you say about the efficiency, I suppose at least it will be an improvement on the current boiler (when it was working)!