Solid Fuel AGA to heat water?

[mellwaters100]

Hello,

I recently acquired an old solid fuel aga which has a 135 gallon boiler in it. As this is currently dismantled and I will be rebuilding it shortly, I am trying decide whether to put the boiler in, or leave it out.

I am hoping that I can get some qualified views on this. Any search brings up either "You are better off without it" or "It makes too much hot water". So, really looking for real experience as to whether this is practical in use, and / or if it has any real impact on cooking performance.

Here's the situation.

We have an oil boiler that has failed, so only have an immersion heater for the water. As this is a top entry (short) heater, takes for every to get a tank full of hot water. Constantly melting the contacts on the heater! Will not be replacing the boiler - oil far too expensive!

The AGA will be positioned directly underneath the existing cylinder and would be a short pipe run to the cylinder (2m horizontal / 2.5m vertical).

My thought is that DHW would effectively be free using the heat from the AGA. On the flip side, if someone empties the hot water tank whilst the ovens are being used, the boiler fills with cold water and core temp reduces a little? Although, the boiler is on the left side of the heating chamber, ovens on the right, so how can the water drastically lower the oven temp?

I suppose my thought is that, hot water is typically drawn off outside of main cooking times, i.e. morning and evening, so any reduction in core temp of the AGA would have time to recover?

Secondly, how important is the size of the cylinder in this equation? Currently, the cylinder is 110 litres where AGA Living suggest a 290 litre tank for a 135 gallon boiler. Am looking at trying to secure an ebay model and seeing a couple in the 210 litre area.

So, from real life experience, would a solid fuel AGA with a 135 boiler fitted, connected to 210 litre cylinder (with a possible towel rail heat sink) allowing for 1 or 2 drains of hot water per day together with "easily" cooking 1 main meal per day - be a realistic / attainable setup?

All views would be appreciated - am really torn with this. It seems a no-brainer to get this setup as all the pipework is already in place, especially as we don't have, and will not be getting a dedicated CH+DHW boiler.

Thanks!

 

[mysteryman]

You do not get something for nothing - water heating AGAs use more fuel. It does reduce the cooker temperature somewhat when you've drawn hot water off. They are lovely cookers, but a solid fuel one is quite a bit of work, and dust. The 135 gallon boiler means 135 gallons [about 600 litres] per 24 hours, so that alone should give you some guidance as to cylinder size. There's quite a bit to assembling an AGA, especially a solid fuel cooker, as they can overheat if the inner workings are not airtight.

 

[oilhead]

Echo mysteryman's comments. Don't forget to make sure you have a good sound flue.

 

[wsts]

As an ex AGA engineer I can confirm the previous 2 comments are correct and good advice, both posters being situated in Shropshire make me wonder if they also have had past dealings with AGA too ?

 

[mellwaters100]

Thanks all, for your replies.

Have decided to leave the boiler out when I rebuild - one less thing to worry about!

I have another question, which I hope you guys may have an opinion on. The stove I have is a solid fuel but was converted to oil, wishing to convert back - it is a deluxe model.

Question - 7 or 8 bar grate? What's the real difference. Am guessing that the 7 bar has bigger gaps, meaning more airflow, meaning hotter fire but chance of fuel falling through when riddling? 8 bar smaller gaps so more chance of clogging up with ash?

Speaking with local coal merchant and he recommended Duck Eggs fuel which, he tells me produces little ash and needs little riddling.

Any recommendations on the grate?

Thanks!!

 

[mysteryman]

That fuel will be Phurnacite or similar. I lived with a solid fuel AGA in the '80s and it just gobbled this type of fuel. I found anthracite in stove nut size to be best. AGAs were designed to burn coke from a gasworks.

As far as I remember, the 8 bar grate is for four oven or water heating models, and the 7 bar for two oven dry models. They didn't make four oven solid fuel with water heating. I doubt if it is worth changing to a 7 bar if you have an 8 bar even if you leave out the boiler - which is a very good idea.

 

[leezer3]

My family lived with a two-oven coal Aga for nearly 15 years.
Assuming it was topped up morning and night, you got about enough hot water for 2 1/2 baths before it starting running out.

Generally worked quite reasonably, although you want to make sure you don't get one with a worn riddle plate ring if at all possible. (We had several incidents over the years where the round ring bit slipped out of alignment and got stuck. This then entails letting it cool for most of a day, then taking the top off and fishing out the fuel before reseating and going through the pain of relighting)
You also don't want to relight at all if you can help it, as they take an awful long time to get back up to temperature, and are a general pig to light.

The oven temperature setting is also marginal at best, and you'll find it differs based on when you last topped up the fuel, and the fuel type. Basically though, you'll get the hang of it after living with it for a few weeks.