Warranties

The Company has warranties with various terms ranging from 18 months for parts to 25 years for certain heat exchangers. The Company has an obligation to replace parts if conditions under the warranty are met. A provision is made for estimated warranty costs at the time the related products are sold based upon the warranty period, historical trends, new products and any known identifiable warranty issues.

Changes in the warranty accrual are as follows:



	Three months ended
	March 31, 2019			March 31, 2018
Warranty accrual:	(in thousands)
Balance, beginning of period	$	11,421		$	10,483
Payments made	(1,106		)	(1,222		)
Provisions	1,109			1,527
Balance, end of period	$	11,424		$	10,788

Warranty expense:	$	1,109		$	1,527