Q: Piping installation for Split Types

[brianubaldo]

please give me some data of piping installation if the required length of the pipe is exceed.

for example; the required piping length is 100M maximum, and the actual length of the condensing unit to the evaporator is 120M in the installation site.

do i need to change the required pipe diameter for suction and discharge? please give me some data or charts of piping installation.

[saillar]

Need more Data, what is the size of the system, manufacturers recommended pipe size, refrigerant, lift if any, rooftop installed condensing unit or ground mounted? Type of compressor. Manufacturer & Model.

[brianubaldo]

saillar;

the unit is 1hp. condensing unit in roof! is there a specific tables for installation? if the requird length is exceeded? should i change the standard pipes diameters?

[daddyfixit]

Hey brianubaldo,

Have you contatcted tech support for the mfg. of the equipment you're installing. I'm sure they would be willing to help you to avoid a warranty issue.

Up sizing does sound applicable to avoid added pressure drop. An extra 20M could choke down the system. However, maybe a slightly larger CU would be better. If the mfg. gives a "maximum piping length", that compressor might not be able to provid the proper velosity with longer pipe sized for the correct pressure drop. There might be a maximum balance point where size and distance will give optimum velosity and restriction. Past that you will have to sacrifice one for the other.

Don't forget to calculate all the fittings in the length (traps, ells, ect..) as they have pipe length equivalents due to restriction.


Wish you the best...

[Thermatech]

Please can you advise
1/ Manufacturer name
2/ Model of indoor & outdoor unit
3/ Refrigerant type
4/ Exact hight difference between outdoor unit & indoor unit.

I would be very interested to look up details of this exceptional system on manufacturers web site.

1 hp input is about good for 12,000 btu / 3.5 kw cooling at indoor unit.
Most standard split systems of this size will have max pipe lenght of 30m & the most expensive top of the range systems up to 50m. The bargan basement systems will have much shorter pipe lenght of up to 20m
The vertical hight seperation is normally alot less than the max pipe lenght. So a system with max pipe lenght of 50m might have a vertical hight seperation difference of 30M.
A typical system installed with max pipe lenght of 50m will have a large refrigerant pressure drop & reduction in cooling performance. The manufacturer will rate the unit cooling performance at a short pipe lenght & then provide a correction chart so the installer can estimate the expected cooling performance at the pipe lenght installed.Typically this might be around 10% reduction in cooling performance for each 10M of interconnecting pipe.

Therefore I would suspect your system to have zero cooling at 100m.
Therfore my interest in seeing technical details of this exceptional split system.

It would be interesting to see the oil return arrangement for this system.

BTW if your system is 10hp then some top of the range split systems on R410a can now run up to 70m pipe lenght & will have aprox 20% reduction in cooling capacity at that pipe lenght.

[brianubaldo]

tnx for the time thermatec,

sorry i had post the wrong information.
10M only is the manufacturers required piping length and the pipe size is 1/4dia suction and 3/8dia in discharge.

i have a problem in our units. it is a samsung split types. i work here as a technical support. some of the installer exceeds the required piping length and the results is weak cooling. they exceeds the length about 2-3 meters.

the capillary of the system is designed installed in CU. is it posible that i change the design? i will put the capillary in indoor unitS? and i will make the pipes smaller to increase velocity of refrigerants?

[Thermatech]

You might find that the 1/4 dia tube is the pre expanded liquid line flow from the outdoor unit to the indoor unit & the 3/8 dia tube is the suction gas return from the indoor unit to the outdoor unit when in cooling mode.

Any pipe length extra to the manufacturers max length will result in some reduction in cooling.

If you have fixed speed compressor then it can only pump a fixed volume of refrigerant depending on the pressure drop of the installed pipe length installed.

I would suggest you install this type of unit at your office with extra pipe connected & experiment with refrigerant trim charge to find the optimum refrigerant charge.

The compressor life will be reduced & you will have more warantee returns of compressors from systems installed with excessive interconnect pipe length.

[nike123]

tnx for the time thermatec,

sorry i had post the wrong information.
10M only is the manufacturers required piping length and the pipe size is 1/4dia suction and 3/8dia in discharge.

i have a problem in our units. it is a samsung split types. i work here as a technical support. some of the installer exceeds the required piping length and the results is weak cooling. they exceeds the length about 2-3 meters.

Weak cooling is because they probably don't fill additional charge of refrigerant required for that length. That amount of additional length should not make significant impact at oil return of AC if indor and outdoor unit are at similar level. It will, however, reduce capacity of unit few percents.

the capillary of the system is designed installed in CU. is it posible that i change the design? i will put the capillary in indoor unitS? and i will make the pipes smaller to increase velocity of refrigerants?

If it is heat pump type, you cannot change placement of capillary tube.

[brianubaldo]

If it is heat pump type, you cannot change placement of capillary tube. 28-04-2008 09:49 AM


how can i recognized if it is a heat pump type or not? sorry if its a noob question but im curious. i would like to know many designs/systems in refrigeration.

.
Weak cooling is because they probably don't fill additional charge of refrigerant required for that length. That amount of additional length should not make significant impact at oil return of AC if indor and outdoor unit are at similar level. It will, however, reduce capacity of unit few percents.


i had checked the unit and the charge is sufficient we add addidtional charge of refrigerants because we add additional lentgh. the pressure is relevant to the ampere rating in the label.

Q> what would be the consequences if i exceed the manufacturers required piping lentgh? and is it possible that i would make the piping little smaller than the manufacturers design if i exceed the required length?

is there a reference or standard datas about pipe sizes on different capacity of units?

[nike123]

how can i recognized if it is a heat pump type or not? sorry if its a noob question but im curious. i would like to know many designs/systems in refrigeration.

How could you be technical support when you don't know answer to this simple question?
What is your occupation and what is your expertise in support you give to others?

You could find out is it heat pump or not from model no. or, by looking if the outdoor unit have reversing valve

.

i had checked the unit and the charge is sufficient we add addidtional charge of refrigerants because we add additional lentgh.

How did you checked this? Only by measuring current?
Also, how did you (or did you) checked this allegedly smaller cooling capacity

the pressure is relevant to the ampere rating in the label.

That doesn't mean much.

and is it possible that i would make the piping little smaller than the manufacturers design if i exceed the required length?

You cant go smaller than 1/4 and 3/8.

is there a reference or standard datas about pipe sizes on different capacity of units?

I don't know for such reference.

Did you checked that failed compressors and establish what was damage (overheating because of damaged bearings or something else)?

[brianubaldo]

tnx to all..

[paul_h]

Maximum is maximum not to be exceeded by the installer using generic advice or charts no matter what. Systems are pre charged to a certain length, then allow more if you add refrigerant charge up to the maximum. Above the maximum is no go, no matter how much more ref charge you add, since the pipe diameters are a given. The only way to get more information is to contact the manufacturer to see if they will OK lengths above maximum with a larger pipe size. No generic chart will give you this data because it's the manufacturer that has to design and OK the install.

edit:
Also important, how much of this pipe length is vertical, since 100m is a hell of a long pipe length