Posted by: @iantelescope

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@jamespa 

Heat-Ex-changer upside down ?

 

Is it possible that my Heat -Exchanger was installed with the temperature difference , or gradient , hot to cold, in the same direction between input and output ports?

I know, I have asked this question before ,so please accept my apologies in advance  ............. a seniority deficit!

My EAC  Heat Ex-changer has no markings other than the EEC directives .

I have been here before ...............but as Oliver Cromwell did not say to the General assembly in 1651,  I do " think it possible that I could have been  wrong", maybe the heat ex changer is fitted upside down!

 

 

 

 

As you state, it is not so much orientation as flow direction.

If the PHE is mounted vertically, the flow from the heat pump should enter at the top of the primary side and return to the heat pump from the bottom of the primary side.

The water from the heat emitters should enter at the bottom of the secondary side and exit from the top of the secondary side.

@jamesPa & @derek-m

Heat Ex changer confusion!

My heat ex changer has a hidden torn label giving the  (assumed standard) EEC Port connections , K1,K2,K3 and K4. as,

K1 =  Primary Hot water Input

K4 = Primary Input Cold, Return

K2 = Secondary Cold  Water Input

K3 = Secondary Hot water Output

My Heat Ex changer has been configured such that :

K1 = Secondary Cold Input

K4 = Secondary Hot Output

K3 = Primary Hot water Input

K2 = Primary Cold Water Return

I have a Heat Ex changer that has the correct gradient , Hot to Cold,  but is a mirror image !

Does this mirror image, Outputs and inputs being reversed have any effects on the Heat Ex changer performance?

Time for stiff coffee!

@iantelescope 

A photo would be useful.

@derek-m 

Many thanks derek , my heat ex changer is , probably , been wrongly mounted  !

My heat ex changer has a hidden torn label giving the  (assumed standard) EEC Port connections , K1,K2,K3 and K4. as,

K1 =  Primary Hot water Input

K4 = Primary Input Cold, Return

K2 = Secondary Cold  Water Input

K3 = Secondary Hot water Output

My Heat Ex changer has been configured such that :

K1 = Secondary Cold Input

K4 = Secondary Hot Output

K3 = Primary Hot water Input

K2 = Primary Cold Water Return

I have a Heat Ex changer that has the correct gradient , Hot to Cold,  but is a mirror image !

Does this mirror image, Outputs and inputs being reversed have any effects on the Heat Ex changer performance?

The heat pump is feeding hot water from the heat pump into the bottom of the Heat Ex changer port  K3 instead of the K1 port .

The Flow directions are ,however, opposing .................that was why I previously assumed that the heat pump was correctly configured.

Mental gymnastics of Heat Ex changers?

Posted by: @derek-m

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Normal practice is to carry out a legionalla cycle once every 7 to 10 days, so during the Spring through to Autumn period there should not be a problem.

But do you need to do it all? 45 to 50 legionella is dormant, 50 degs 90% is killed within 2 hrs. If you have a decent turnover of hot water do you need the cycle at all?

We just store at 50 and heat to that twice per day. Anything in there is dead. Most of the cylinder contents are either at above 45 and dormant or above 50 and actively being killed.

Main water in UK is treated to kill just about anything, so if it doesn't exist, what are you killing?

@johnmo I think the danger is not from the water supply as such, more a case of air borne bacteria. (Someone will be along to correct me if I am talking wrollocks. Toodles.

Posted by: @toodles

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@johnmo I think the danger is not from the water supply as such, more a case of air borne bacteria. (Someone will be along to correct me if I am talking wrollocks. Toodles.

Airborne may be relevent in an open vented cylinder but

Water is treated by chlorination or other means and passed under pressure around the country in a sealed system. Enters house, goes into an unvented cylinder all sealed from atmosphere. Only in contact with air as it comes out of tap etc. 

@johnmo I seem to remember when large outbreaks were traced to an air conditioning system as water passed through cooling processes involving mesh filters and evaporation processes or similar. After several lethal outbreaks, H&SE regs were brought in to prevent air borne transference of the spores responsible. Toodles.

Posted by: @toodles

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@johnmo I seem to remember when large outbreaks were traced to an air conditioning system as water passed through cooling processes involving mesh filters and evaporation processes or similar. After several lethal outbreaks, H&SE regs were brought in to prevent air borne transference of the spores responsible. Toodles.

Not much to do with the legionella cycles on an unvented cylinder?

@derek-m 

Photographs may not help ....but here goes.

The remains of the label gives the following information:

Designed and Manufactured

according to

PED/97/23

EAC

A drawing :

k2 top left

k3 bottom left

k1 top right

k4 bottom right

The Standard EEC designations are given online for K1,K2,K3 and K4.

 These photographs show the Heat Pump feeding hot water into K3 .

These photographs show the HEX feeding radiator hot water into the second, radiator, motor.

This photographs show the HEX outputting the primary , HP Cold return from K2.

This photographs also show the Cold Radiator water returning to K1 on the HEX.

Sorry about the photographs ...............difficult to show the pipe connections.

I  now doubt that the mirror imaging , with inputs mirrored to outputs would make any appreciable difference....................but I could be wrong.

@johnmo Also, if I remember correctly, the first instance of legionella came about at some sort of convention of old retired Legionnaires (hence the name given to the problem). I seem to also remember that the BBC had a case of it in one of their cooling systems (at Broadcasting House, London I think, memory is a little hazy now). How the spores get into what is effectively a closed loop system of water distribution is outside of my Bailiwick! Regards, Toodles.

@iantelescope

For most efficient heat transfer, the primary inlet should be at the top so that the water is cooling as in flows down to the exit at the bottom. The secondary inlet should be at the bottom, so that the water heats up as it rises, with the exit being at the top.

I'm not certain if using the primary as the secondary and vice versa will cause any reduction in efficiency. You could try asking the manufacturer.