Brazed plate heatex

icy78

Just wondering. On this BPX 410-050 (BG) there are 2 in and 2 out. The manual calls for , boiler side F1 in, and F4 out. DHW side, F3 in and F2 out. This particular htex is piped opposite. As in; the outs and ins are correct but the boiler side is on the F2, F3 ports.
Anyone know if that makes a performance difference?

Jim Hankinson

Best performance is with boiler flow one direction, domestic the opposite.

icy78

Jim Hankinson said:

Best performance is with boiler flow one direction, domestic the opposite.

Yes I agree also. And it is counterflow now. And it would be counterflow if the piping were reversed. I'll draw a picture on a back of an envelope I don't really know




Okay there is a pic. So if boil in and boil out were moved to F1 and F4 and domestic hot water in and domestic hot water out where moved to F2 and F3. Would that make any difference to the performance of the heat exchanger. Remember that the instructions, say the hot process lands on F1 and F4 and the cool process on F2 and F3 so back to my question , does it make any difference in anyone's experience or has everybody always piped them correctly?🙂

This may all seem like a stupid question but I don't know the answer so to me it's not a stupid question :-) :-)

GroundUp

Either or, as long as it's counterflowed will perform the same

mikeg2015

Counterflow should operate quite a bit more efficient. Heat rises, cool fall. So boiler water flow downward, DHW flow upward. Chevrons are angled to be optimized for this.

Don’t know how much but probably 10-20%.

Alan Welch

The way I read it, you want to swap boiler water and domestic water on the plate heat exchanger?

icy78

Ok. Answer from Xylem. Can pipe either way (as long as its counter flow.) They didn't know why the instructions dont make that clear.
The fella that installed it originally told me, "well why can't I pipe it that way?, I don't see why not."
Well Im having issues with it and wanted to know FOR SURE that swapping the piping was not contributing to the issue.
It'll be a week before i get back tho.

hot_rod

Doesn't seem like the ports are generally labeled? As long as in and out are correct I don't see a difference in which side is which?

Counter flow puts the hottest fluid against the cooler fluid, higher ∆ equates to more higher heat transfer, the basic hydronic formulas shows the HX..

icy78

> @hot_rod said:
> Doesn't seem like the ports are generally labeled? As long as in and out are correct I don't see a difference in which side is which?
>
> Counter flow puts the hottest fluid against the cooler fluid, higher ∆ equates to more higher heat transfer, the basic hydronic formulas shows the HX..

Yeah the ports are labled and called out as to which ports to pipe to in different modes. But as many have surmised, it doesnt matter.
I emailed Xylem (B n G) about it ,and they sent me the same info I read on-line, but they stated it can pipe either way, no matter what the specs show.🙂
So now I KNOW, that the opposite, but still counterflow piping gives no change in performance. Whereas before, it was purely conjecture.👍

ratio

What issues are you having?

EBEBRATT-Ed

I have seen them with the ports not marked and you need the cut sheet to get it right.

I have seen them with the two right hand ports for 1 circuit and the 2 left hand ports for the other circuit

or they criss cross. Depends on the mfg and how it is built

icy78

> @ratio said:
> What issues are you having?

Poor performance. I'm waiting on parts for the heating loop side of this so haven't been back.
Its part of the same system that i have another thread on. Its the Head Scratcher 🙂 thread.
(I dont know how to show that URL here.)

Alan Welch

Have seen both domestic and boiler sides plugged up wit sediment that reduces flow. Often times just back flushing can improve performance noticeably.

icy78

> @Alan Welch said:
> Have seen both domestic and boiler sides plugged up wit sediment that reduces flow. Often times just back flushing can improve performance noticeably.

Thanks. I'll find out. Its easy to remove and flush.

hot_rod

If you can accurately determine either temperature drop across both sides, or flow , you could plug that data into a HX simulator and predict the expected performance.

If they are pumped properly the channel velocity should keep the plates clean.

If one side sees fresh water they can lime up, just like a tankless water heater or any HX. Run an acid cleaner thru it or take it to a radiator shop and have them "cook" it clean.