Andrew, can I ask about weather compensation when used with a hot water cylinder? I'm just looking into this as we have a Baxi Duo-tec combi-boiler (using combi hot water for the kitchen but also a HW cyl at the far end of the bungalow for the bathrooms, plus two other zones for CH). If I fit a weather compensator (I've checked the Baxi website, possible) and allow the boiler to run at a lower condensing temperature, how do I best ensure the HW cyl is heated to 60deg as required for legionella safety, etc? Is there an override input to the boiler which can be fed from the HW zone signal from the timer or valve? Complicated by the fact I'm using a combi boiler as a system boiler. Someone else suggested rigging up a timer to the immersion heater and letting it heat the HW cyl to 60deg once a week! But I'd like to know how I would otherwise do it. I gave up after 40 mins on hold to Baxi....
Thanks for posting I run UFH (no radiators) on an Ideal Logic 24+ . I have installed a opentherm and set to around 17 which seems to supply UFH at around 40ish. My blending valve is set at 35 (it's a small house well insulated). What you are saying is that the Hot water will not run at full temp although I only have the hot water on the boiler set to 60.
Hi, thanks for putting up these videos. I’ve got a job with underfloor heating downstairs, rads upstairs and unvented cylinder. In this video, do you have a system boiler pumping around the close coupled tees? Then a pump for hot water and rads and a separate pump for the underfloor?? I’m hoping to use an Ideal Vogue with a hot water priority. I don’t suppose you have a wiring diagram for this system? Thanks
Hi Andrew, Great video as always. I assume that the underfloor will have to wait for the rads to heat and be satisfied before the underfloor will click on weather comped? What if the rads have a long heat up time? I've done this with priority hot water but not used the priority side of things for the rads. Could the rads have gone on the weather comp side?
No the rads and ufh heating run at the same time. The curve for the weather is set for the the radiator circuit, the underfloor heating takes this lower temperature and still utilises the blending valve and actuator and room thermostats
So, the rads and UFH run under WC - which the WC slope is set for the rads. DHW priority, run up to max boiler temperature for DHW reheat. What was the customer complaining about to get you in?
@@johnburns4017 controls where not working. Heat miser controls are too complicated for most customers to set up and use. When I checked I found the boiler running at 70c for ufh and explained the inefficient design flaw. We have made it as efficient as possible with the boiler he has by running at weather compensated radiator temperatures rather than high temperature. Still a compromise but the best I could do for him. The boiler should now run below 50c for heating and much of the time below 40c.
Nice! Have an ongoing issue with a new Keston Heat 2 that comes with what they call an 'optional weather compensation kit' which is just an outside sensor... Unfortunately it doesn't offer any adjustment to the curve so the flow temp isn't high enough to satisfy the demands of the building - it's effectively useless.
Hi, some advice if you would be so kind. I wired an ideal weather compensation kit into my ideal logic max 30. I have no cylinder stat or hw zone. Only CH. So only SL1 is connected is wired to my time clock EPH-R37. I powered up and I lost control and couldn’t power off the boiler. Manual says you need to wire SL2 to HW off, but I don’t have a cylinder stat with HW off. You mentioned a permanent live to SL2 is required? Or P2?
It already has one. The boiler has to run at 70 as it has to.make hot water. The 70c goes to the mixing valve. The mixing valve has to be set to work at the lowest expected outside temperature so is set to 50c. Most of the time the floor needs less than 30c. This causes the floor to overheat at all but full load. This overheating causes complaints. Weather compensation reduces this issue to an acceptable level. A WC electronic mixing valve gives perfect comfort.
is it possible to run the Viessmann Vitodens 100-W as you did for this ideal boiler? Mine is set to DHW priority. This kills the heat to the radiators while the cylinder heats up. I'd much prefer to have both the radiators and the DHW on at the same time even if it takes longer for the water to heat up. And of course as soon as the cylinder has heated up, revert to the lower temperature to benefit from better efficiency.
Ive added weather comp to my ideal logic system boiler and it has started to cycle on and off repeatedly at 84c when the controls call for heat rather than running low and slow….any ideas what’s going wrong?
@@andrewrussell548 you need to ensure that the main switch live is live for both hot water and heating demand. The weather comp module only needs an off signal when hot water is not needed. Itz a stupid system imo but it's how it's designed.
So I’ve added a link in SL2 from “L” to “in” which has helped (no high temps as previous) but in CH the boiler appears to be cycling in for 20 seconds to heat then running the pump until the temp drops (2 mins) then repeating the cycle. In HW function it appears to be temp controlled from the dial rather than the tank settings.
