Reversed Return & Supply

BerkshireSkiBum

<span style="font-size:12pt">I have a newly installed Alpine APL105 condensing boiler. My question is about the system's  Return & Supply connections. The</span><span style="font-size:12pt"> system diagram (Figure 32) on page 47 of the Installation, Operating manual shows the “<span style="text-decoration:underline;">First System Connection Tee</span>” to be for system RETURN and the “<span style="text-decoration:underline;">Second System Connection Tee</span>” to be for the system SUPPLY.</span>

<span style="font-size:12pt">My system has these connections reversed.</span>



Should I be concerned? I note that under the Boiler Protection section of the manual (pg95) refers to "Inversion Limit" which would cause a hard lockout and shut down the boiler. This is the result of "incorrectly attaching the supply and return piping". I have noticed that the return temperature is at times 2-3 degrees higher than the supply, owing to the reversed connections.  I have not had this system fault occuring. The Return and Supply tees are within 6" of each other on the primary loop.





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Zman

Do you have a picture?

The location of the tee's is relative to the flow in the 2 loops. Do you have a picture of your piping?

Carl

unclejohn

System pump

Your suplly tee should be the one closest to you system pump.

BerkshireSkiBum

piping diagram

The attached piping diagram "Near Boiler Piping" shows what I would have expected to see for Return and Supply from the boiler. In my installation those connections are reversed.

Zman

The manual

The drawing in the manual shows one correct way to pipe your system. There are variations that may also be correct.

Picture?

Carl

BerkshireSkiBum

As installed system Picture

Thanks for the reply. Just to be clear on this I've attached a picture of the system as you requested.  It just sees that injecting the supply ahead of the return will cause the system to sense an incorrect temperature drop. I've seen the Sage control display a return higher than the supply.

CMadatMe

Question

That zone pump to the left of the return is supply? Can you take a pic of the entire piping?

Paul48

Carl

It appears as though he is circulating to the return of the primary, as opposed to circulating away from the primary supply.

Zman

Details

Is the boiler at the upper left? It is pumping into the return on the boiler? Which way is the the circ on the left pumping? It looks like down.

Carl

BerkshireSkiBum

System w/ All Circ Pic

A fuller system picture. Until now I hadn't noticed the flow arrows on the Grundfos circulators. I've shown the direction of flow as marked on the circulators. So relative to the pg. 47 piping diagram it appears that the "From System" and "To System" flows are reversed in the primary loop.

CMadatMe

How many

Inches to center are between the two tees?

BerkshireSkiBum

Inches between Return & Supply

exactly 7 inches on center between Return & Supply

bob_46

Arrow

Which way does the arrow point on the air scoop ? Why are you pumping toward the x-tank instead of away ?

BerkshireSkiBum

AMTROL?

If you're referring to the AMTROL air purger, the arrow is left to right per the picture. Don't know the answer to "Why are you pumping toward the x-tank instead of away ? ". 

I did not install this system - I'm the homeowner and just looking to validate the system as installed. Thanks.

bob_46

Tees

The tees for the boiler are in the proper order for the way your system is piped. Your system is not piped anything like the drawing on pg47. The Mfg shows the primary loop pumps on the supply yours are on the return. The Mfg. shows the primary loop pumps

pumping away from the x-tank yours pump toward. Some plumbers don't believe in pumping away and like to put their pumps on the return where they see cooler water.

CMadatMe

Measure

Each Zone Supply and Return Temps. Issue may be nothing more then that you are over pumping the zones.

BerkshireSkiBum

Tees / Pump order / Mfg warranty

Thank you for confirming that this is a proper installation. I should expect that the Mfg would approve it for warranty purposes.

BerkshireSkiBum

Zone Circulators / Pumping speed

The Sage2.1 system controller measures and reports Return/Supply temps and will initiate a boiler shut down if Return temp execeeds Supply for an unspecified "limit time". Although I've seen the controller report a 2-3 deg Return over Supply  temp my system hasn't shut down. I have is an instant read thermometer and will try it out.



The zone circulators are set on the middle speed and are driving SlantFin baseboard. I'm guessing perhaps that the shortest run (~20 ft of baseboard) and closet to the circulator itself could be driven with the low speed. What is the best stradegy for this?



Also I noticed that the boiler circulator in my system is a Grundfos 15-56FRC wase are the zone circulators. The Installation manual specs call for a Grundfos 26-99FC which should be factory supplied with the ALP105.

 

CMadatMe

Problem Solved

Boiler pump is an issue. Your not moving water out of the HX fast enough.

R Mannino

The Last One

we did had a 0011 Taco on it.

bob_46

proper

I was confirming that your system is piped backwards. The boiler tees are in the right order for a system piped backwards. I would have piped it according to the Mfg. instructions.