I am looking to replace my existing Vaillant heat-only boiler with a new Vaillant ecotec plus 630 system boiler (30kW). I have a megaflo hot-water cylinder, a central heating system (serving 21 radiators) and an orangery built last year (6m x 4m) with underfloor heating. Through running some tests, it has been found that the heat exchanger on my existing boiler is partially blocked.
The issue I have am currently having is that whenever I turn on the UFH only, the boiler, after about 60-70 mins of running, will start continually anti-cycling (modulating) even though the heat demand is enough to warrant continuous firing of the boiler. This has boiled down to the fact that the heat demand to the boiler (when only the UFH is on) is less than the minimum the boiler can deliver.To get around this, I need to turn on the CH so that the boiler will continuously fire and the UFH will remain on.
Having had a few heating engineers come over to assess the issue, the general consensus/recommendation is for a new system boiler to be installed along with a Low Loss Header (LLH). The installer I have in mind to install the new system is recommending the FlexEJ 3/4" DN20 LP 30kW LLH. Does anyone have positive/negative views about this LLH, and whether one flow and return on the secondary side is sufficient? Is there an alternative LLH that may be more suitable?
The issue I have am currently having is that whenever I turn on the UFH only, the boiler, after about 60-70 mins of running, will start continually anti-cycling (modulating) even though the heat demand is enough to warrant continuous firing of the boiler. This has boiled down to the fact that the heat demand to the boiler (when only the UFH is on) is less than the minimum the boiler can deliver.To get around this, I need to turn on the CH so that the boiler will continuously fire and the UFH will remain on.
Having had a few heating engineers come over to assess the issue, the general consensus/recommendation is for a new system boiler to be installed along with a Low Loss Header (LLH). The installer I have in mind to install the new system is recommending the FlexEJ 3/4" DN20 LP 30kW LLH. Does anyone have positive/negative views about this LLH, and whether one flow and return on the secondary side is sufficient? Is there an alternative LLH that may be more suitable?
