Baxi HT330 install question

Scott M_3

Thanks for the answer Mike. Do you know if the pump speed is adjusted using the QAA73 control. Im trying to post a few pics, let me know if you would change anything.

Scott M_3

Baxi HT330 install question

Hi everyone, I had a Baxi HT 330 installed over a year ago and it worked well over the winter but I noticed that when all 3 zones called for heat there seemed to be a large drop in the heat output from the basebaords. The installer connected all the zones to the header that was piped with 3/4 inch copper. Since the instruction that came with the Baxi gave no dirrection on what size of header to use I thought the install was done right. After downloading the install direction from Laars for the Mascot, which i'm told is the same boiler, I now know that I need 1 1/4 header and return. I will be changing this to make it right but I have a few questions.
-Should I use the 1 1/4 pipe or should I go for the 1 1/2 since I might be adding a fourth zone in the future.

-Should I install a Spirovent? All the baseboards have a vent on them to bleed the air and I have never had a problem with trapped air.

-The internal Grundfos pump needs to be bleed before startup using the small silver disc on pump. Im not sure how to do this, can anyone tell me.

-Does anyone have some photos they could post of a completed install with an external pump. With the fourth zone I made need one in the future.

-Does anything need to be done to the internal expansion tank, it has a valve built in but not sure if I need to drain anything.
Thanks for the help, I know its alot of questions.

[Deleted User]

Baxi HT330

There is really no need to use a 1-1/4 header the system should work fine with 3/4. The only thing that could cause some issues would be some piping issues or check and make sure the pump is on the highest speed. If the pump is not on high speed, it will not produce the proper head and flow to move the BTU's needed to heat your house.

If your system is removing the air properly now I see no need to add a spirovent.

If you need to bleed the pump back out the silver screw until you get a steady stream of water and then close it back up. Make sure to cover the cover of the control panel to prevent water from getting in there.

You shouldn't have to do anything to the internal expansion tank.

If you have further questions just respond and post your e-mail. I will help where I can.

Scott M_3

Thanks for the answer Mike. Do you know if the pump speed is adjusted using the QAA73 control. Im trying to post a few pics, let me know if you would change anything.

Bob Forand

Baxi

Hi Scott,

Do you have the external sensor on your boiler ? I ask because your heat output dial is not turned up all of the way.

Where are you located - what is your typical winter temps like ?

What footage of baseboard do you have connected to this boiler ? Is the baseboard connected with copper throughout the system ? If not are they crimp style pex fittings ?

Do you have the tools to measure the supply temp and the return temp from each zone when all zones are calling ? I normally use a strap on thermometer.

How often are you having to purge the pump of air ?

The pump speed switch is on the side of the pump, be careful about trying to change the setting of the pump, it also changes the whole dynamics of your heating system.

Bob

Scott M_3

Baxi HT330 install question

HI Bob,

Thanks for responding to my question, here is the info you requested about my system.
-I do not have the outdoor reset sensor, I turned down the temp so it will condense more. Temp here in Massachusetts has not been really cold yet.

-The footage of the baseboard is; Zone one has 36 feet, Zone 2 has 18 feet, and zone three has 20 feet. The whole system is 3/4 inch copper.

- I dont have a strap on thermometer but when all 3 zones call for heat you can not feel to much heat coming off of zone 1 baseboards.

- I have not had to purge the pump but if I upgrade the supply and return header to 1 14 inch I will need to do it.

Thanks again for the help.

Bob Forand

Hi

Hi Scott,

I wouldn't be concerned with changing the piping to 1-1/4". Your load on the boiler is only 43K or so,which is using 600 BTU per foot of baseboard. The piping arangement that you have will handle that load.

The reason I asked about the thermometer is to figure out your dt on each zone. The temperature difference between supply and return from each zone. You can use the retun ball valves to balance the zones. You can restrict the smaller zones a little so that when all three are calling at once the larger zone will get more flow. You do that by measuring the temps, and try to balance the dt on each zone.

As far as the expansion tank, the one built in is capable of handling up to 14 gallons of water. Your system probably has much less than that. If I remember correctly, 3/4" copper carries 2-1/2 gallons per 100 feet.

If you add another zone, it still wont be necessary to add another pump. The internal pump will handle up to 160 feet of baseboard. However, with that being said I would look into having a bypass valve installed. The bypass valve is used on zone valve systems to help smaller zones overcome the high pressure of the pump.

All in all, it looks like a good install. I wouldn't be concerned with upgrading the manifold to 1-1/4". It would not be money well spent. However, I would look at trying to find a way to balance the zones so that the heat distribution is better. That would be money better spent. You can use any type of thermometer and zip tie it to the tubing.

Hope this helps, good luck.

Bob

Scott M_3

Thanks for the advice Bob, it really helps.
Scott

Nanuk

baxi 380 ht

hi i bought a baxi ht 380 and my plumber has never done one can someone please post some pictures from a typical installations and also do i need pumps for all 3 zones or can i just use zone valves thanks

Bob Forand

Hi Bill

Hi Bill, where did you buy your HT boiler ? I hope that it was a reputable supplier. Maybe that supply house should help your plumber understand how to get your system together and get the boiler properly tuned in. You are asking for a lot of issues with this boiler if it is not properly set up. Just seeing pictures is not the way to approach the installation. It really does take some research and planning.

It must be set up with a combustion analyzer and should not just be hung on the wall. There are settings in the QAA controller that need to be set. Do you have plans for the condensate ? How small are the three zones you are planning ?

Where are you located ?

Peter Turk

Gas Line Connections on Baxi?

The Baxi manual specifically says that the gas line into the boiler should be 3/4". However most residential flex gas lines are 1/2" with 3/4" connections. Has anyone noticed this before? Will a 3/4" black pipe line work with a 1/2" flex hose on the end into the boiler?

Peter

Bob Forand

No

The short answer is no, the Baxi requires 3/4". The reason is that it needs the volume to make hot water. Remember it fires immediately to 126,000 btu's to make the hot water.