I've fixed something. I think. Is this right?

[Mottie]

11 of us are staying in a farm for the new year. 6 bedrooms but only two bathrooms. We've been here before and the owners let us also have use of the bathroom in an adjacent cottage that is now only used for storage. Us blokes use it and the girls have the two bathrooms in the main barn. Combi boiler, Worcester I think. Anyway, when we turned up, the owner apologised and said that the shower is only running at Luke warm but she couldn't get anyone out at short notice and she'll try tomorrow. I tried it and it was barely getting warm. I looked at the pressure gauge and it was dead on the line between the red and green portions of the scale. 1 bar I think. I connected the flexi hose and topped it up to 1.5 bar. The heating came on and the shower was plenty hot enough. Can low pressure cause a tepid hot water flow - I'd have thought it wouldn't fire up at all? More important, have I fixed it? If so, I can tell the owner not to get a plumber out.

 

[CBW]

If the heating came on, and you’re getting hot water, I’d say there’s still an issue, probably diverter valve/motor related. Try it without the heating, see if it still works. Could be intermittent though.

 

[ericmark]

Some boilers use flow switches other use pressure switches, likely it is now OK.

 

[Mottie]

If the heating came on, and you’re getting hot water, I’d say there’s still an issue, probably diverter valve/motor related. Try it without the heating, see if it still works. Could be intermittent though.

No, what I meant was the heating came on automatically when the pressure was topped up. I turned the room stat down and it went off. The shower was then constantly hot. When I went there last night for a shower, I switched the heating back on. I can get hot water as normal with heating on and off. I was just curious as to why I was getting Luke warm water at the shower and taps when there clearly wasn't enough pressure in the system for the heating.

 

[kidgreen61]

I can't see a correlation between system pressure and DHW performance.
WB are one of the few boilers that don't have a low pressure switch, and will often keep working with very little, if any pressure at all.
A lot of other boilers will show a fault code if pressure drops to below 0.5 bar or so.

 

[Madrab]

At the end of the day if it's working then smashing. It could be the increased pressure is allowing better flow through the plate or similar but have you fixed it, hard to say.

If it's all working though, getting someone out to repair will be a waste of time (and money) as there will be no fault to find.