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[mlappin]

I took my copper out of basement and replaced it with pex and used pipe straps to hang it ! Doesn't look all that bad! I thought I was having flow restrictions but it didn't make a difference what a waste of money! This year I switched my 40 plate heat exchanger for a 100 plate and see no difference! I guess the only thing left is a bigger pump!!

What size copper did you take out and what was the size of the pex you installed? Takes 1 1/4” standard pex to equal one inch copper.

[schoppy]

Hey fireboss, don't know how long your run is to the house from the boiler but it may be that you are at your max gpm. Have you done a flow test to see where you are at? Point is, depending on length of piping, pipe size and load configuration the pump size may not increase your flow rate.

When I changed out my P&M to my Heatmaster G400 I did flow tests on both of my lines (shed and house).I did flow tests last year on the P&M also so I could compare my changes. With suggestions from slimjim (using monoflow tees and increased primary loop size inside the house to 1 1/4" pex) I changed out my lines (in the house) from a series setup to a primary/secondary loop setup and even added a third load and it is working great. I increased my flow from 6.8 gpm last year to 9.4 gpm this year with the same pump. I also replaced about 50 feet of 1" pex in my shed with 1 1/4" and increased my flow there about 1 gpm but I only have one load there. All my buried pex I left as is since I wasn't going to dig it all up. About 95 feet buried to the house and about 150 feet buried to the shed. Typically on 1" pex, from what I have found on distances like this you are looking at around 8 gpm for an average flow rate.

[fireboss]

Iam only 14' away from my house and a nother  10' in the basement  I used the 25' on the therm pex the came with boiler when I got it , and got the 10' uninsulated pex from them and put pipe rap around it in basement! my chief complaint is when the temps got down to close to zero ,  my boiler is at 195 - 185 and my hot water base board is 165 to 170 ! And my house is 65 to 68. Witch we could live with, but  when its like 15 above the house can get up to 74  i have a big enough stove to handle the load just cant get it across my now 100 plate exchanger! My temp on my oil burner only still only gets to 170! When I switch to oil its goes up to 180!

[RSI]

Iam only 14' away from my house and a nother  10' in the basement  I used the 25' on the therm pex the came with boiler when I got it , and got the 10' uninsulated pex from them and put pipe rap around it in basement! my chief complaint is when the temps got down to close to zero ,  my boiler is at 195 - 185 and my hot water base board is 165 to 170 ! And my house is 65 to 68. Witch we could live with, but  when its like 15 above the house can get up to 74  i have a big enough stove to handle the load just cant get it across my now 100 plate exchanger! My temp on my oil burner only still only gets to 170! When I switch to oil its goes up to 180!

So you are running from the boiler through 35' of 1" pex, then through a 100 plate HX then back through 35' of pex to the OWB? What size pump are you using?

[schoppy]

When the temps are close to zero and you're using your oil boiler, can you get your house up to 74 degrees?

[fireboss]

Yes oil burner gets the house up to 74 no problem! Iam running taco oo7 iam guessing it's to small ? It's the only thing left lol! Iam only loosing like five degrees on and average day!

[mlappin]

That would be my somewhat educated guess although with only 35 foot of run you’d think a 007 would be enough, but Thermopex is more like 7/8’s ID correct?

I ran the 1 1/4” pex in my shop but am using small pumps, was much cheaper to buy large line and small pumps than the other way around.

[RSI]

With such a short run you could gain some flow with a larger pump but the velocity will get pretty high. You should be around 8gpm right now but that is assuming only 70-80' of 1" pex in the loop. If you have any pex elbows or a lot of other fittings it will drop off from that fast.

If you try a larger pump, I would go with a Grundfos 26-99 and put in series with the 007. Then wire it to only come with the thermostat in the house. Also put a manual switch on it so you can turn it off when the house is heating ok with just the 007.

[mlappin]

With such a short run you could gain some flow with a larger pump but the velocity will get pretty high. You should be around 8gpm right now but that is assuming only 70-80' of 1" pex in the loop. If you have any pex elbows or a lot of other fittings it will drop off from that fast.

If you try a larger pump, I would go with a Grundfos 26-99 and put in series with the 007. Then wire it to only come with the thermostat in the house. Also put a manual switch on it so you can turn it off when the house is heating ok with just the 007.

Would a Delta T work in this situation? With a call for heat it should ramp up and supply more water as the Delta T widens?

A two speed pump with high only kicking in with a call for heat would be ideal here.

[fireboss]

I don't have any fittings ! That's why I got rid of the copper I had 90's and 45s all over the place! Now with the pex its a straight shot ! I  Realy think its only 60' round trip with 3 feet head! What about putting another oo7 in series? I have my spare to put  in and I have one for the pool that I don't use in the winter!

[RSI]

You would gain a little with another 007 but not a lot. The head pressure is just really low on them.

[fireboss]

I keep the pump running 24\7, and I also have a 007 on the oil burner side of the exchanger that runs 24\7  ,and then when zone valve opens, I have another 007 that comes on and sends it up stair's! I just don't under stand why I can't get the 180 -185 in the house, when my 6048 is @ 195  with no load! Even when it's 60 out  and iam sorry I hijacked this post I just realized it, again iam sorry!

[slimjim]

Have you actually measured the water temps coming out of your boiler and then again at the entrance to the building?

[fireboss]

No slim, but I have a temp gauge on my return and its only loosing 5  to 8  and it Idol's most of the day when it warm out ! I don't use much wood!

[hondaracer2oo4]

You only exchanging 5-8 degrees from the inlet side of the FPHE to the outlet of the FPHE on the OWB side? What is the in/out temps on the indoor boiler side of the FPHE? Slow flow caused by a small pump on the OWB side would cause excessive drop in temperature across the FPHE, not a small drop in temperature returning to the owb. Any chance that you don't have the OWB line and the Indoor boiler line flowing in opposite directions through the FPHE? How is the FPHE plumbed into the indoor boiler side of the heating system?