Cheapest possible with a warranty recommends
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If you need a cheap system boiler of more than about 15kw, the lowest cost solution is usually to use a combi, take the DHW from the combi to the kitchen sink only, and use an S plan on the heating circuit to drive an unvented cylinder.
Although many system boilers are just combis with some bit removed, economies of scale and market realities often make a 24kw combi cheaper than an 18kw system boiler.
If you really want cheap, Heatline, Vokera and Ideal have some good deals. If you really want a long warranty, then you aren't going to get the dirt cheapest.
If you need a cheap system boiler of more than about 15kw, the lowest cost solution is usually to use a combi, take the DHW from the combi to the kitchen sink only, and use an S plan on the heating circuit to drive an unvented cylinder.
Although many system boilers are just combis with some bit removed, economies of scale and market realities often make a 24kw combi cheaper than an 18kw system boiler.
If you really want cheap, Heatline, Vokera and Ideal have some good deals. If you really want a long warranty, then you aren't going to get the dirt cheapest.
Reply to the thread, titled "System boiler" which is posted in Boiler Advice Forum on Plumbers Forums.
We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.