Search results

How do you use a manometer in that situation?

Any idea what he meant?

I’m getting lost here! You said in #5 "it doesn't, by design, allow the pump speed to fall any further once the residual head falls to 100mB, the pump speed was remaining at ~ 75/80%" Am I right thinking the pump speed modulates to try to achieve a setpoint dT? I assume the varying boiler...

I'm not clear what your problem is. If it's just that the pump doesn't turn down below a certain point so (assuming the boiler is controlled on flow temperature) you lose some condensation, maybe you just have to live with it.

Perhaps some red Hermetite or similar on the seal. Stops most leaks

That's what I thought. So by body in #3 you mean the pump head? Is it an O-ring? Replacing that might do it, if a new one didn't come with the new head.

Reference to the screws made me think you'd just removed the motor. If you fitted a complete pump, isn't it a faulty unit? You wouldn't normally expect to separate the motor, just fit the whole thing. Less I'm missing something.

Is it possible to adjust the 100mb setpoint, perhaps Vaillant can help? If on falling heat demand the pump reaches its allowed minimum head (hence minimum flow), the dT falls. Does it maintain flow temperature, so return temperature rises, or maintain return temperature, so flow temperature...

Along with London buses, Olympic swimming pools, Wales etc :giggle:

Sounds like you just replaced the motor. It's usually an O-ring seal, if so it's worth smearing it with silicone grease. I assume you've cleaned up the mating surfaces. If all else fails you could replace the pump body. Last one I did the price for the motor only was the same as the whole pump...

I trust you mean in the back of the car :giggle:

They're too pathetic to bother replying to. They don't answer any questions, or explain why they disagree, just repeat the same nonsense.

There's this thread https://www.diynot.com/diy/threads/valiant-vs-viessman-heat-only-boiler.609063/post-5452724, which also contains a ref to a long discussion Several threads came up when I searched for residual head

IIRC this was discussed a while back. Can you find that thread, to save thinking it out from scratch? I can't understand the Vaillant curves either, in partic the horizontal part. I assume residual head curve should show the bare pump Q/H curve, minus the boiler internal losses, varying as Q^2...

I have gas boiler/rads CH. According to the Met Office site RH for the next week where I live varies between 44 and 92%. At outdoor temperature 10°C and indoor 20°C indoor RH is around 1/2 those figures. Doesn't seem to cause me any problem.

You can't tell an idiot like JohnD anything, I'm going to stop trying.

Do they? All crimes or just rape and sexual assault? For the latter, immigrants and men of asian ethnicity are more likely, on a per capita basis if not overall.

I mean what if usually means. If white British men do commit more crimes, it wouldn't be a surprise as they make up the bulk of the male population. And it still doesn't mean we should be bringing in foreign criminals.

Not that old trope again. Even if it were true, so what? White British men are our problem, but it doesn't mean we should be bringing in foreign ones.

Even if you don't live longer, it will feel like it :giggle: