Replacing Trianco Eurostar 110 - any help appreciated please

[rossm]

Hello,


Posting for the first time to get some advice on replacing an oil-fired boiler (Trianco Eurostar 110 STD - states 110 BTU/hr or 32KW). This boiler is being kept alive with parts & regular fettling & has eaten up a set of baffles, 2 transformers, 2 photocells, 4 nozzles, an oil pump, 2 solenoids, a set of spark contacts and a control box since we moved in 7 years ago and is running so inefficiently that it seems to fire more or less continuously when the heating is on. Space for its replacement is not a problem as this boiler sits in the laundry/utility room of an old, stone built, large & rambling farmhouse (16 radiators) but efficiency is, hence the questions I wanted to get more knowledgable opinions on.

I think there are 4 specific questions I'm needing to work out answers to :-


1. Am I right in thinking that I am risking revealing / creating weaknesses in the pipework by moving to a combi system ? Our house water supply pressure can be wound up pretty high via the external cock so could quite likely supply enough head to drive it. Not that hot running water is much of an issue (see below).


2. Would any boiler models allow us to heat water for radiators only i.e. isolate 'off' the hot water to the tank ? We rarely use hot water as we have electric shower & never use a bath.


3. Is there any big efficiency downside to overspecifying the heat output of the boiler i.e. in the Worcester Bosch Greenstar range, I guess the 25/32 might be sufficient but would the 32/50 be capable of running as efficiently ?


4. What are the upsides or downsides to going with an external boiler ?


Really appreciate any thoughts & thanks


Ross

 

[SimonG]

1. Before you think combi, how many bathrooms/baths/showers.
2. Heat only boiler or system boiler. Sounds like your current system is gravity hot water, if you keep a cylinder it will have to be fully pumped.
3. Don't go for the 32/50 wb it's a very poor machine. Just because your existing boiler is 110,000 btu's doesn't mean that's what you need. Need to size existing boiler to suit requirements.
4. Space and no smells with an external.

 

[rossm]

Thanks SimonG. :smile5:

You answered ...

1. Before you think combi, how many bathrooms/baths/showers.

... Only one just now but I'm looking to install second bathroom with bath & shower this summer.

2. Heat only boiler or system boiler. Sounds like your current system is gravity hot water, if you keep a cylinder it will have to be fully pumped.

... Thanks.

3. Don't go for the 32/50 wb it's a very poor machine. Just because your existing boiler is 110,000 btu's doesn't mean that's what you need. Need to size existing boiler to suit requirements.

.... Not buying a notoriously bad boiler model is exactly the kind of thing I hoped to get advice on, so really appreciate the tip-off. Regarding my question for over-specifying heat output though, is there a downside (if the boiler model was a good one of course) ?

4. Space and no smells with an external.

... No negatives at all then ?

 

[dontknowitall]

I'm just going to back up SimonG here as I fully agree with what he says (and he also knows what he's talking about).

If you're considering a Worcester External 32/50 I'd go for it!!

Brilliant boilers! (imho)

There are a couple of negatives but there not too much of a concern to be honest:

1. Can only be serviced in reasonable weather. If you can imagine what it's like crouched down for an hour or two trying to keep your tools dry, keep the burner dry, etc ...
2. They have a built in frost thermostat which kicks in during really cold weather. This is all very well - as long as you don't have a powercut! I use anti-freeze inhibitor which is more expensive but does negate much of this cold weather worry.

Other than that, it's positives and one of the best is that you can't really hear it working. A small advantage is nearly half the work can be done before disconnecting your existing boiler (assuming it's still working to some extent).

[Edit]

Just read Simon's post re-size!

32/50 is probably okay but much the best to see if it's the right size for your house first!

 

[rossm]

Thanks dontknowitall.

As I can only see a WB 32/50 available an internal ... Greenstar Utility 32/50 - Worcester, Bosch Group UK homeowner site but a 25/32 available as external ... Greenstar Camray External 25/32 - Worcester, Bosch Group UK homeowner site , the external idea might be a non-starter depending on sizing.

I had considered that servicing might be an issue as the place where it would need to be sited is very windy, dark, muddy and gets a lot of water dripping down from a barn roof. Frankly, if it ever got to the point of needing fiddling with as much as current boiler, it would be a nightmare if it was outside !!! Also, as it can get pretty cold here in my part of inland Scotland, frost protection might be a more important consideration too.

Regarding sizing, is there a thread on the forum that would help me work out what heat output would be right for me ?

 

[kimbo]

Hi Rossm,
A lot of good points made here.
First of all you will regret getting a combi after about 5 years because they will start giving problems and more expensive to repair. An ordinary condensing boiler only has the burner and a couple of thermostats to go wrong, the external controls are easy to replace and cheaper ( I have just replaced a worcester 3 port valve for a heatslave, the price of the valve was over 120pds. a 3 port valve from the merchants was about £60).
Every engineer has their own favourite boiler, I favour Grant and I wouldnt touch a Worcester as it is a pain to service.

The best system would be an unvented cylinder and condensing boiler.

Dont oversize your boiler because the condensing boilers are at their most efficient when they are condensing so you need to size it up as near as you can, the boilers can be downrated or uprated depending on what one you go for.
This site will give you your correct boiler size.
Replacement Boiler Size Calculator
Outside boiler would be best if location suited.

 

[rossm]

Thanks kimbo. I'll have a look at Grant boilers too but thanks for the link & the explanation for not 'oversizing'. That calculator is suggesting 47kW & by far & away the most heat loss through the solid stone walls ...

The dwelling type is detached with double glazed windows with wood/plastic frames.
The external walls are solid wall, 220mm thick.
The roof is pitched with more than 75mm of insulation.
The Dwelling is in Scotland.

The following three major contributors to the heat requirement
are all affected by the levels of insulation.

The WINDOW heat loss is 5.76 kW
The WALL heat loss is 19.67 kW
The ROOF heat loss is 3.26 kW

47kW seems very high to me (bearing in mind it's 32kW at present) but as we also have a double aga in the kitchen that will be contributing quite a lot of heat to the back of the house. We also run a solid fuel stove in the main room for a few hours in the evening which is designed to output 5kw.

I'm now thinking that insulating with spray foam where possible behind the plasterboard might be an essential investment but I've no idea what the stuff might cost. It's something I'd be happy to do myself room by room if the materials are cheap enough and easy enough to source.

 

[sraheens]

All can I say try considering boilers Firebird condensing boiler they also do outdoor models. That is if there up there for sale. From having installed them on the West Coast of Ireland outdoor indoor and I have never had a problem.
Wish you well with the upgrade

 

[WHPES]

Your existing problems with the burner constantly firing and poor efficiency will not be caused by the boiler itself, but rather the system it is driving. Unless you revamp the system - flush out, check that it is piped up correctly and make modifications, ensure you have suitable thermostatic control, replace undersized radiators with the correct size etc, you will not achieve anything by replacing the boiler alone.

As for combi boilers, I look after dozes of them and only the ones at the bottom end of the market give contant problems. Don't be put off. I would never hesitate to recommend Grant or Trianco machines, but steer away from Warmflows and similar machines. Not a fan of Firebird either as I seem to have more call outs to them than some other makes.

When servicing external boilers, I always pick a nice day. In any case, some of my work involves working in muddy trenches, fixing frost damage, leaking troughs, so working on a boiler outside is no big deal.