Dirt in caleffi manifold flow meters

rhl

Many of my caleffi manifolds flow meters are dirty and some don’t work (I assume as a result).

Is this fixable without replacing them??

hot_rod

Did you run a system cleaner when the system was commissioned? That can help clean out most of the debris and dark colored fluid.

You could try a cleaner and a flush, but stuck meters usually have debris jammed in them

Does the system have a magnetic separator, or at least a Y strainer?

rhl

yeah we have a caleffi dirt sep, cleaner, no.

The system is (now) filled with a 10% glycol mix so if the cleaner isn’t an additive we won’t be adding it.

Jamie Hall

Actually any type of flowmeter will be affected by dirt and particles in the circulating water — it's not just Caleffi units. It's inherent in the types of flowmeters suited for relatively low flows.

Nos. That being said, it is a symptom — a nuisance, to be sure, but a symptom — of a dirty system as a whole. This can, with time, cause a variety of other problems — some of which (like stuck pumps) can be a bit more than a nuisance.

So. The solution is to clean the system and keep it that way. The glycol should, if it is intended for the purpose, have corrosion inhibitors suited to the materials (systems with iron or steel in the take one chemistry, systems with aluminium take a different one (applies to cars, too, which is why you don't mix anitfreeze types and always use the right one for the vehicle, by the way). The two chemistries don't play well together.

(Oddment: I mentioned that the two chemistries don't play well together. In fact, they form a particularly nasty gel in fine passages… there are a few premium glycols for vehicles which are suited for any metal.)

These inhibitors are chemically used up over time, so the effectiveness must be checked from time to time.

Now if the glycol concentration is low (as in this instance), corrosion inhibitors can and should be added separately.

You also need particulate filters — which must be cleaned — and, if there is any iron or steel present, magnetic particle filters. Which must also be cleaned.

Don't shoot the messenger…

hot_rod

10% is a pretty weak glycol solution?

Dow suggests no less than 30%, mainly because the inhibitor package will be to diluted to do much protection

If for some reason you want a low % like that, add more inhibitor. The manufacturer of the glycol can provide inhibitor boost packages

rhl

thanks yes, I’ll write more in a seperate post on my system. It’s an (split) air to water heat pump. I ended up with glycol because of the manufacturers requirement in oddly enough, cooling mode.

We do need to add the the inhibitor.

hot_rod

In cooling mode running cold enough you could freeze water, so they prefer glycol.

If the flow indicators are rust stained or black from bad glycol, that is hard to clean out of those plastic indicators.

Screenshot 2024-10-19 at 5.48.11 PM.png

rhl

Yes, that is the sort of problem. The original system was of course only water, and we flushed all the fluid out of all the jaga rads/radiant loops, so the only dirt left at the minute is in those flow valves.

I've bought all replacements now, i'll work on putting them on.

Separately on a related separate topic on my (brand new) cooling manifold has a stuck balancing valve (in the fully closed position), what can i do to get it loose? when i use the little white cap to turn it open, it doesnt budge.

hot_rod

you need to pop the white cap off, flip it over to use it as a wrench. When the cap is pressed down on the manifold it locks the valve from turning.

I have not heard of one sticking that it won’t budge in either direction?

rhl

Yeah the plastic wrench didn’t do it at first.

I had to use a set of pliers on it very carefully and then it unstuck and my plastic tool took it from there